Encyclopedia of Bioethics: Vol 2
Crowe, Raymond R. 1984. Electroconvulsive TherapyA Cur-rent
Perspective. New England Journal of Medicine 311(3):163-167.Culver,
Charles M.; Ferrell, Richard B.; and Green, Ronald M.1980. ECT and
Special Problems of Informed Consent.American Journal of Psychiatry
137: 586-591.Gert, Bernard; Culver, Charles M.; and Clouser, K.
Danner.1997. Bioethics: A Return to Fundamentals. New York:
Oxford.Group for the Advancement of Psychiatry. Committee on
Medi-cal Education. 1990. A Casebook in Psychiatric Ethics.
NewYork: Brunner/Mazel.Heshe, Joergen, and Roeder, Erick. 1976.
ElectroconvulsiveTherapy in Denmark. British Journal of Psychiatry
128:241-245.Kesey, Ken. 1962. One Flew over the Cuckoos Nest. New
York:New American Library.Merskey, Harold. 1991. Ethical Aspects of
the Physical Manipula-tion of the Brain. In Psychiatric Ethics, 3rd
edition, ed. SidneyBloch and Paul Chodoff. Oxford: Oxford
University Press.Ottosson, Jan-Otto. 1985. Use and Misuse of
ElectroconvulsiveTreatment. Biological Psychiatry 20(9):
933-946.Smith, Daniel. 2001. Shock and Disbelief. Atlantic
287(2):79-90.Strayhorn, Joseph M., Jr. 1982. Foundations of
ClinicalPsychia-try. Chicago: Year Book Medical Publishers.Taylor,
John R.; Tompkins, Rachel; Demers, Renee; and Ander-son, Dale.
1982. Electroconvulsive Therapy and MemoryDysfunction: Is There
Evidence for Prolonged Defects? Bio-logical Psychiatry 17(10):
1169-1193.Willner, Paul. 1985. Depression:
APsychobiologicalSynthesis. NewYork: Wiley.EMBRYO AND FETUS I.
Development from Fertilization to BirthII. Embryo ResearchIII. Stem
Cell Research and TherapyIV. Religious PerspectivesI. DEVELOPMENT
FROMFERTILIZATION TO BIRTHThe ethical relevance of studying human
developmentappears when one asks which stages of the human life
cycleembody significant ethical concerns. Between birth anddeath,
the human organism is a person, equipped with thefull measure of
basic human rights. This much is not reallycontroversial, and the
debate primarily concerns the prenatalphase of development. Do
human rights accrue to theunborn all at once, for instance at
fertilization? Do theyinstead arise in a gradual manner, based on
the variousprogressive steps through which the prenatal human
organ-ism acquires significant person-like properties? Besides
per-sonal rights, are there other ethically-significant values
andproperties that would justify a respectful treatment of em-bryos
and fetuses? An understanding of prenatal develop-ment is a
necessary, albeit in no way sufficient, condition foraddressing
these issues successfully.To understand the basic biology of any
sexually repro-ducing organism, one needs to grasp the primary
concept ofthe life cycle. The life cycle of humans includes
fertilization,cleavage, gastrulation, organogenesis, fetal
development,birth, child development and puberty, gametogenesis
andagain fertilization. It is through the germ-line that the
lifecycle persists from generation to generation. On the otherhand,
the somatic cells (which comprise all the cells of thefetus, child,
and adult that are not directly involved inreproduction) belong to
an inherently mortal entity, thehuman organism, whose fate is
senescence and death. Oneturn of the life cycle defines one
generation. Fertilization andbirth define the beginning and end of
the prenatal phase ofdevelopment, which is comprised of two stages:
embryonicand fetal.The embryonic phase initiates with
fertilization, themeeting of the male (sperm) and female (oocyte)
gametes,giving rise to the zygote. At fertilization, a new,
diploidgenome arises from the combination of the two haploidgenomes
included in the gametes. The zygote divides severaltimes (cleavage
stage) to form a blastocyst. The cells of theblastocyst, called
blastomeres, are separated into two parts:an outer layer, called
the trophoblast, that eventually contrib-utes to the placenta; and
an inner cell mass that contributesto the future embryo. About six
days after fertilization, theblastocyst attaches to the endometrium
(the epithelial liningof the uterus). This marks the beginning of
pregnancy andfurther development depends on intricate biochemical
ex-changes with the womans body. While the trophoblastinvades the
uterine wall, the inner cell mass undergoesfurther stepwise
differentiation processes that lead to theformation of the
embryonic epiblast (the precursor of theactual human individual)
and several extraembryonic struc-tures (Figure 1). The embryo then
undergoes gastrulation,the process that starts with the formation
of the primitivestreak. This is the crucial developmental step,
common to all
animals but the most primitive invertebrates, by which thethree
basic germ layers of the embryo are formed. These arecalled
ectoderm, mesoderm, and endoderm.From the third to the eighth week,
the process oforganogenesis involves the differentiation of the
three germlayers into specific tissues and primordial organs. The
earli-est stage in organogenesis is called neurulation and
startswhen a specific area of ectoderm turns into the primordiumof
the nervous system. During organogenesis, many genesthat are
crucial to development are activated, and complexcelltocell signals
insure the proper differentiation of vari-ous cell types, as well
as the movement and migration of cellsto their proper places in the
developing embryo. For somecell types, this involves long-range
navigation. For instance,the gamete precursors must travel from
their initial positionnear the yolk sac to the primordial gonads.At
the end of the embryonic phase, many importantorgan systems are in
place, at least in rudimentary form. Thefetal phase is
characterized by further differentiation andmaturation of tissues
and organs, as well as considerablegrowth, especially towards the
end of pregnancy. In the latefetal phase, the nervous system
undergoes an acceleration ofsynapse formation and maturation of the
brain, which isincreasingly sensitive to outside cues. This process
continueswell after birth.Specific Developmental Stages in
DetailEspecially in early development, specific
developmentalprocesses seem more meaningful than others in the
ethicaldebate about the moral status of human prenatal life.
Theseare described in more detail.GAMETOGENESIS AND FERTILIZATION.
The embryo isusually defined as coming into existence at
fertilization andbecoming a fetus when organogenesis is completed
(eightweeks after fertilization). These borders are not
sharplydefined. The definition of an embryo thus cannot avoidbeing
operational and context-dependent. The term conceptusis useful to
denote any entity resulting from fertilization,when no reference to
a more specific stage is intended. Anadditional complication
results from the significant overlapbetween the final stages of
female gametogenesis, fertiliza-tion, and initial
cleavage.Gametogenesis involves a special type of cell
divisioncalled meiosis. When primordial germ cells (which
arediploidi.e., they have two complete sets of chromosomes)enter
meiosis, their DNA is duplicated so that there are nowfour copies
of each type of chromosome (a condition calledtetraploidy). In the
first meiotic division, there are geneticexchanges within each
group of homologous chromosomes,which then separate into diploid
daughter cells. In thesecond meiotic division, there is no further
round of DNAduplication. Each chromosome in a pair is allotted to
aseparate daughter cell, now haploid. Each primordial germcell thus
gives rise to four daughter haploid cells.In the male, all four
cells resulting from meiosis ulti-mately become functional
spermatozoa. In contrast, in thefemale, only one of the daughter
cells becomes an oocyte, theother three cells are discarded as
polar bodies. In addition,female meiosis is not completed until
after fertilization hasoccurred. During each ovarian cycle of the
sexually maturefemale, one oocyte progresses partially through
meiosis butis arrested in the middle of the second meiotic division
at thetime it is discharged from the mature ovarian follicle into
theoviduct. If the oocyte is fertilized, meiosis is
completed.Within the newly fertilized egg, the male and female
pronucleiundergo a protracted migration towards each other,
whileDNA is duplicated within both. Thereafter, both
nuclearenvelopes disappear and the chromosomes derived from themale
and female gamete are involved in the first cleavagedivision. Thus
the first genuine diploid nucleus is observedat the two-cell stage
only (30 hours after initial contact ofsperm and oocyte). While
fertilization usually occurs close tothe ovary, the conceptus is
gently nudged towards theuterus, a voyage lasting about five
days.Both through recombination of gene segments duringthe first
meiotic division, and through random assortment ofhomologous
chromosomes in gametes, genetic novelty isgenerated. In other
words, gametes are genetically distinctivein relation to their
diploid progenitors and do not simplyreflect the genetic structure
of their parent organism. In asense, gametes are distinctive
individuals in relation to theorganism that produces them.
Fertilization creates geneticnovelty of a different sort, by
combining two independentpaternal genomes. The zygote is
genetically distinctive be-cause it represents the meeting of two
independent parentallineages. Thus genetic novelty appears twice
per turn of thehuman life cycle.CLEAVAGE, PLURIPOTENTIALITY, AND
TWINNING. Dur-ing cleavage, the zygote divides into smaller
embryonic cells.At the 16-cell stage, the embryo is called a morula
and a firstdifferentiation into two cell types is initiated. The
trophoblastis the cell layer that will soon connect with the
uterine wall,whereas the inner cell mass includes the cells of the
later stageembryo. At the blastocyst stage, a central cavity
(blastocoel)is formed. If a blastomere is removed from the inner
cell
FIGURE 1Derivation of Tissues in Human Embryos
Epiblast
EXTRAEMBRYONICTISSUES
- Cytotrophoblast
source: Gilbert, 2000.
mass of a blastocyst (as, for instance, in
preimplantationdiagnosis), the blastocyst is still able to produce
a completelate embryo and fetus. This illustrates a fundamental
princi-ple called regulation, or regulative development. Within
theearly embryo, cell fates are not definitely fixed but
largelydepend on interactions with neighboring cells, so
thatdevelopment adjusts to the presence or absence of
specificenvironmental cues. The molecular basis and the
genesresponsible for these cues are increasingly well known.At the
blastocyst stage, the inner mass cells are pluripotent(i.e., they
have developmental plasticity) and are able toparticipate in the
formation of most cell types of the adultorganism, as shown for
instance by experiments with cul-tured immortalized blastomeres,
called embryonic stemcells. Recent research does suggest that
individual blastomeresacquire some degree of molecular specificity
quite early.However, this inherent bias that tends to drive
everyblastomere towards a specific cellular fate can easily
beoverridden at this stage.Around day 6, the blastocyst has hatched
from thesurrounding zona pellucida (the outer envelope of theovum)
and is ready for implantation. As it attaches to theendometrium,
two distinctive layers appear in the inner cellmass. The ventral
layer (hypoblast) contributes to the primi-tive yolk sac. The
dorsal layer soon differentiates between theembryonic epiblast that
will contribute to the embryotobe, and the amniotic ectoderm lining
the newly appearingamniotic cavity (day 78). This twolayered
structure iscalled the embryonic disk. All this happens as the
blastocystburrows deeper into the uterus wall and the
trophoblastcomes into close contact with maternal blood vessels.
Thetrophoblast also produces human chorionic gonadotropin(hCG),
which is the substance detected in pregnancy testsand is essential
to the maintenance of pregnancy. Abnormalconceptuses are very
common until that stage and areeliminated, usually without
detectable signs of pregnancy.Inversely, fertilization occasionally
results in a hydatidiformmole. This structure consists of
trophoblastic tissue andtherefore mimics the early events of
pregnancy (hCG isproduced), without their being any actual
embryonic tissuepresent.The term pre-embryo was often used to mark
theembryonic stages described so far. This term is sometimesshunned
in contemporary discourse, as it has been suspected
to be a semantic trick to downgrade the standing of the
veryearly embryo. Yet even writers like Richard A.
McCormickbelonging to the Catholic tradition, sets great store by
themoral standing of the earliest forms of prenatal develop-ment,
have expressed doubts about the validity of thissuspicion (1991).
More importantly, doing away with theterm preembryo does not solve
the two underlyingconceptual problems that this term addresses. The
firstensues from the cellular genealogy linking the zygote to
thelater stage embryo and fetus. Only a small part of the veryearly
embryo is an actual precursor to the late embryo, fetus,and born
child. Whatever terminology one wishes to use, noaccount of early
development can avoid sentences such asthis, written by Thomas W.
Sadler in 2000, [t]he inner cellmass gives rise to tissues of the
embryo proper, or terms suchas the embryotobe. This is an
inescapable consequence ofthe fact that the late embryo includes
only a small subset ofall the cells that originate with the zygote
and blastocyst(Figure 1 shows the complex genealogy of embryonic
andextraembryonic tissues in human development). The secondproblem
arises from the fact that the early embryo has adegree of freedom
as regards its final numerical identity.Until about 12 days after
fertilization, twinning can occur.In other words, until that stage,
a single embryo still has thepotential to divide in two embryos,
ultimately developinginto two separate persons. Therefore there is
no intrinsiconetoone relationship between the zygote and the
lateembryo, as there is between the late embryo, the fetus, andthe
born human.GASTRULATION. Gastrulation begins with a wave of
cellu-lar movements that start at the tail end of the embryo
andextend progressively forward. Future endoderm and mesodermcells
slip inside the embryonic disk through a groove calledthe primitive
streak (day 14). The anterior end of the streakis called the node.
Of the cells that migrate inside the streak,some form the endoderm
and others will lie atop theendoderm and form the mesoderm.
Finally, those cells thatremain in their initial position on the
surface of the embry-onic disk become the ectoderm. Gastrulation
sets the overallorganization of the embryo in a definitive way. The
mainaxes (anteriorposterior, leftright) are defined under
thecontrol of two central signaling centers: the node (which isthe
equivalent of the organizer discovered by embryologistsworking on
frog and chick embryos) and the anteriorvisceral endoderm.Recent
data from molecular genetics have partiallyuncovered the molecular
basis of axis determination. Thedetermination of the
anteriorposterior axis involves theHOX genes, a set of four gene
complexes. Since HOX geneslocated at the front end of a HOX complex
are expressedat the front end of the embryo, the arrangement of
thevarious genes within each complex remarkably reflects theplace
at which they are expressed in the embryo along
theanteriorposterior axis. The four HOX complexes thusprovide four
genetic images of the lengthwise arrangementof embryonic
structures. The leftright asymmetry of theembryo (and thus of the
future body plan) is thought tooriginate with specific cells in the
node. In a way that is notfully understood, these cells induce a
cascade of proteinsignals that is different on the left and right
side of theembryo. This results in the synthesis of controlling
factorsthat are laterally restricted. It is supposed that these
control-ling factors and other factors direct the development
ofasymmetric organs accordingly.Through gastrulation, the embryo
arises as a definedentity endowed with a much higher level of
organic unitythan at any stage before. The laying down of the
headtotail axis and other defined spatial features, as well as the
lossof pluripotentiality in many cell lineages, mark the begin-ning
of a single individual human organism and thusprovide one of the
first important dimensions of the onto-logical continuity typical
of the born human.LATER DEVELOPMENTAL STEPS. In the initial step
inorganogenesis, the midline axial section of
mesodermthenotochordinstructs the overlying ectoderm to turn
intothe neural plaque. This structure soon wraps around to formthe
primitive neural tube, out of which the central nervoussystem will
eventually grow. By the beginning of the fetalperiod (eighth week),
the rudiments of the heart, blood andblood vessels, the major
segments of the skeleton andassociated muscle groups, the limbs,
and many other struc-tures are in place. It is noteworthy that
although theprimordial nervous system is one of the earliest
organsystems to emerge in development, it takes the longest timeto
mature. Synaptogenesis (the formation of contacts be-tween nerve
cells) starts on a grand scale only late inpregnancy and continues
well after birth. This is importantto keep in mind when
interpreting early movements of thefetus, visualized more and more
accurately by ultrasonography.These movements reflect the
maturation of local neuromus-cular structures and are not due to
significant brain func-tion, since there is no brain in the sense
of the later, muchmore developed anatomic and functional structure
called bythat name. This is different later in pregnancy, when
fetalmovement is more reactive to the environment and when
itbecomes arguably legitimate to interpret it as behavior,insofar
as it reflects the increased functional capabilities ofthe central
nervous system. Finally, the concept of viabilitybasically reflects
the ability of fetal lungs and kidneys to
support extrauterine life, which is impossible before
thetwenty-second week.As mentioned before, the differentiation and
migrationof early gametes also occurs during the embryonic
phase.This separation of the germ cell lineage from all other
celllineages marks a bifurcation in the life cycle. Unlike
somaticcells, gamete precursors have a chance of becoming
gametesand participating in fertilization, thus contributing to
thenext generation. In a way, the germ cell lineage is
eternalthrough successive turns of the life cycle, whereas the rest
ofthe embryo, the sum total of somatic cells, is inherently
mortal.Extracorporeal EmbryosScience fiction fantasies about the
artificial uterus notwith-standing, only the very first stages of
human developmentcan occur outside the female body. Since 1978, in
vitrofertilization followed by embryo transfer has been a com-mon
treatment of fertility problems. The growth of ovarianfollicles is
stimulated by the administration of gonadotropins.Oocytes are then
collected by laparoscopy and placed in anappropriate culture
medium. Sperm is added and cleavageoccurs in culture until the
blastocyst is transferred in the uterus.With in vitro
fertilization, the early embryo becamemuch more accessible to human
intervention, and this hasraised ethically perplexing
possibilities. Interventional re-search on early embryos has become
possible, raising thequestion of whether it is ethical to produce
human embryosfor research purposes, or whether research should be
done, ifat all, only on spare embryos. These occur when someembryos
are no longer needed for fertility treatment, eventhough they
resulted from in vitro fertilization performedwith therapeutic
intent. Additionally, progress in genetictesting techniques using
very small amounts of DNA hasmade preimplantation diagnosis of
genetic abnormalitiespossible. Single blastomeres are removed from
in vitroblastocysts, their DNA amplified by polymerase chain
reac-tion (PCR), and subjected to genetic tests with appropriateDNA
probes. (Thanks to regulative development, the miss-ing blastomere
is soon compensated for.) In this way,embryos can be screened for
certain genetic defects and onlythose free of defects chosen for
embryo transfer. Thisprocedure is sometimes suspected of being
eugenic, and thecontroversy around it has led to it being outlawed
in certaincountries including Germany and Switzerland.Developmental
Steps and Moral StatusThe biological processes around fertilization
and early em-bryonic development are often accorded considerable
rele-vance in ethical debates, making a detailed description
ofthese processes necessary. This descriptive effort, however,
isnot based on the belief that the facts speak for themselves.They
emphatically do not. In fact, many ethical controver-sies about the
ethics of in vitro fertilization, embryo research,therapeutic
cloning, abortion and the like, are less aboutethics in the strict
sense as they are about expressing diver-gent interpretations of
biology. The marshalling of biologi-cal fact to support apodictic
statements of moral statusinvolves many, usually unspoken, bridge
principles. Theseprinciples involve highly complex notions, such as
unity,individuality, potentiality, and continuity. It is a
commonmisconception that these theoretical concepts
constitutestable, common-sense notions that are merely applied
tobiological entities and processes. In actuality, these
conceptsare themselves given new meanings and qualifications in
thevery process of using them to make sense of biological
facts.Between the realm of ontological categories and the
empiri-cal domain of biology, there is a two-way street.It is often
said that human life begins at fertilization.Strictly speaking,
this statement is meaningless. Human lifedoes not begin at any
point of the human life cycle; it persiststhrough successive
generations. The ethically relevant ques-tion to ask is at what
stage a human individual is firstendowed with important ethical
value and correlative rightsagainst harm. The difficulty is that no
particular step standsforth as a self-evident developmental marker,
both becausedevelopmental events that appear as sharp
discontinuitiesturn out to be protracted processes upon closer
scrutiny (forinstance, fertilization is a process, not an
instantaneousevent), and because the highlighting of one
developmentalprocess over another necessarily involves more or less
plausi-ble philosophical assumptions.Three different concepts of
individuality appear to berelevant: genomic individuality as
established troughfertilization; numerical identity, defined once
twinning is nolonger possible; identity of the self, as sustained
by a functionalcentral nervous system.Fertilization is important
because it newly connects twoparental lineages that were
independent until then. Themeeting of sperm and oocyte gives rise
to a uniquely noveldiploid genome that is not subject to further
change. It willbe the genome of the future person or persons
arising fromthis particular fertilization. This fact is often
misinterpretedaccording to a hylomorphic interpretation of the
genome,where the latter becomes the formal cause of the futurehuman
being (Mauron). (Hylomorphism is the aristotelianand scholastic
teaching that concrete objects, especially
living things, result from a combination of form [morphe]and
substance [hyle].) This interpretation suggests the no-tion that
fertilization is the single crucial step, since the newgenome
appears at that point. This interpretation fails, notonly because
of the inherent conceptual problems of thehylomorphic view, but
also because there exist biologicalfacts such as twinning and
genetic mosaicism that show thatthere is little connection between
genomic individuality assuch and personal identity. Monozygotic or
identical twinsare separate persons, even though they share the
samegenome, that originated from the same fertilization. Thisshows
that genomic individuality does not provide any basisfor the most
essential property of personal identity, namelynumerical identity
through time. To be one and sameperson through changes in ones
biography is an essentialingredient of any workable concept of the
person, and thebiological basis for this property does not
originate beforegastrulation. In fact, much of the organic
singularity andcoordinated functioning as one organism (rather than
sev-eral potential organisms) is established only at that
stage.However, one may want a richer interpretation of thisbasic
criterion of personal identity. Having a biography ofones own is
not just being the same individual throughtime, but also
experiencing a continuity of mental states,which is linked to an at
least minimally-functioning centralnervous system. In fact, nothing
is more central to themodern conception of the self than the
functional persist-ence of a central nervous system that provides
the materialsubstrate of an individual subjective biography. For
thisbiographical, or subjective, identity, it is difficult to quote
adefinitive starting point. It is plausible to place it in
latepregnancy, when the earliest possibility of a continuing
selfseems to be given, but there is no absolute certainty inthis
claim.ConclusionEthical reasoning on this topic often shows a
commonpattern: one takes moral concepts that belong
touncontroversial persons (such as grown humans) and tries toapply
them backwards to the fetus and embryo. However,importing
intuitions pertaining to the ethics of personalrights and interests
onto various forms of prenatal life isincreasingly fraught with
conceptual difficulties as one movestowards earlier stages. Indeed,
the most perplexing problemin bridging human developmental biology
and statements ofmoral standing is perhaps that traditional moral
categoriestend to be all-or-none concepts (either one is a person
ornot, and if so, one is equal in basic rights to all
persons),whereas developmental biology shows mostly gradual
changeand tends to resolve what appear to be discrete borders
intocontinuities. One obvious and popular answer to this quan-dary
is to make ethical standing a gradually increasingproperty of the
developing human organism. On the otherhand, one may query the
underlying assumption that thereis a one-dimensional measure of
ethical concern. Furtherreflection may benefit from a recognition
that ethical con-cerns about human prenatal life are
multidimensional, andsometimes qualitatively, not just
quantitatively, differentfrom the person-centered systems of
ethical values and duties.ALEXANDRE MAURONSEE ALSO: Abortion:
Medical Perspectives; Alcoholism andOther Drugs in a Public Health
Context; Cloning; Death,Definition and Determination of: Criteria
for Death; Femi-nism; Infants; Infanticide; Maternal-Fetal
Relationship; MoralStatus; Reproductive Technologies: Ethical
Issues; and otherEmbryo and Fetus subentriesBIBLIOGRAPHYFord,
Norman M. 1988. When Did I Begin? Conception of theHuman Individual
in History, Philosophy and Science. Cam-bridge, Eng.: Cambridge
University Press.Gilbert, Scott F. 2000. Developmental Biology, 6th
edition.Sunderland, MA: Sinauer Associates.Green, Ronald M. 2001.
The Human Embryo Research Debates:Bioethics in the Vortex of
Controversy. Oxford: Oxford Univer-sity Press.Mauron, Alex. 2001.
Is the Genome the Secular Equivalent ofthe Soul? Science 291:
831-832.McCormick, Richard A. 1991. Who or What Is the
Preembryo?Kennedy Institute of Ethics Journal 1: 1-15.Robertson,
John A. 1991. What We May Do with thePreembryos: A Response to
Richard A. McCormick. KennedyInstitute of Ethics Journal 1:
293-302.Sadler, Thomas W. 2000. Langmans Embryology, 8th
edition.Baltimore, MD: Lippincott Williams & Wilkins.INTERNET
RESOURCESGilbert, Scott F. 2000. When Does Human Life Begin?Website
to accompany Developmental Biology, 6th edition.Available from .II.
EMBRYO RESEARCHIn previous editions of this encyclopedia, the topic
ofembryo research was included within the entry on fetalresearch.
However, during the latter part of the twentiethcentury the issues
arising from research involving in vitrofertilized embryos became
sharply distinguished from issuesin research with already-implanted
fetuses. Moreover, new
technologies such as the development of embryonic stemcells and
the possibility of human cloning raised new ethicalconcerns in
relation to research involving human embryos.This entry will
address the history of human embryoresearch, public policy on
embryo research in the UnitedStates and internationally, moral
considerations, particu-larly the debate on the moral status of the
human embryo,and the relevance of ethical distinctions that have
beenproposed, such as the distinction between research use
ofsurplus embryos versus embryos created specifically
forresearch.The Research SubjectScientifically the product of
conception is called an embryountil eight weeks of gestational age,
when the name changesto fetus. However, contemporary discussions of
embryoresearch customarily restrict the term embryo to the
earlieststages of human development before implantation in
theuterus occurs. This terminology is supported by the U.S.federal
regulations on fetal research, which define the fetus asthe product
of conception from implantation until deliv-ery, thus excluding
non-implanted embryos from the regu-lations (45 CFR 46.202).In
practical terms the embryo as subject of research isthe embryo in
the laboratory, generally the result of in vitrofertilization
(IVF), but possibly developed by other means,for example, through
flushing naturally-fertilized eggs fromthe fallopian tube, or
through somatic cell nuclear transfer(SCNT) of a body cell into an
enucleated egg, a type ofcloning procedure.A variety of terms has
been proposed for the embryo assubject of research:the
preembryo,the preimplantation embryo,the embryo ex utero,the early
embryo.In this entry the simple term embryo will be used, with
theunderstanding that it refers to the embryo in the laboratorythat
has not undergone transfer to a woman. Some com-mentators maintain
that only embryos resulting from fertili-zation of eggs by sperm
are properly called embryos. Thisquestion will be addressed in
later sections when it isrelevant.Early History of Embryo
ResearchUntil the 1990s most research involving human embryoswas
directed toward improving the chances for pregnancy
inlaboratory-assisted conception. These investigations, in
turn,were based on many years of research with animal models,where
virtually all research in the United States has beensupported with
federal funding. It was hoped that proce-dures developed in animal
studies could later be applied tohuman reproduction and embryology,
especially to theunderstanding and alleviation of human
infertility.Attempts at laboratory fertilization of human
oocytes(precursor eggs) showed some promise as early as 1944 in
thework of American obstetrician-gynecologist John Rock
andscientist Miriam Menkin. From that time until the birth ofthe
first child conceived through IVF in 1978, variousapproaches were
tried in order to achieve a pregnancy andlive birth. The work of
Robert Edwards, British reproduc-tive endocrinologist, culminated
in the birth of LouiseBrown after he collaborated with Patrick
Steptoe, an obste-trician who utilized laporoscopy for viewing and
recoveringa mature ovarian follicle containing an oocyte capable
offertilization.According to embryologist Jonathan Van Blerkom,most
current methods used in laboratory-based treatment ofinfertility
have evolved from those used by Edwards andSteptoe and their
predecessors. According to Van Blerkom,this work established the
basic science foundation of clini-cal IVF (p. 9). Without these
four decades of research onfertilizing oocytes, accompanied by
study of the early cleav-age and development of fertilized eggs or
zygotes, the clinicalpractice of IVF, which is an almost
universally acceptedprimary treatment for infertility, would not
exist.U.S. Funding and Regulation ofEmbryo ResearchIn 1975 the U.S.
National Commission for the Protectionof Human Subjects recommended
guidelines for federalfunding of research involving human fetuses,
but stipulatedthat these guidelines did not cover research on IVF
or onembryos resulting from IVF. It proposed that an
EthicalAdvisory Board be appointed to review such protocols,
andthis recommendation was incorporated into federal regula-tions.
In 1978 an Ethics Advisory Board (EAB) was ap-pointed to recommend
a policy on federal funding forresearch involving IVF.In its 1979
report the EAB concluded that research onIVF was ethically
acceptable for federal funding under theseconditions: that all
federally funded research is directedtoward establishing the safety
and efficacy of IVF; allgametes used to develop embryos in research
protocols areprovided by married couples; and no embryos are
preservedin the laboratory beyond fourteen days of development.
TheEABs rationale was based on two main points. First, it
would be irresponsible to offer clinical IVF without doingthe
studies necessary to insure its safety and efficacy. Second,given
the high rate of embryo loss in natural procreation, asimilar rate
of loss could be tolerated for the goal ofeventually achieving
pregnancies and births.The EAB did not distinguish between embryos
createdfor research purposes and embryos remaining from
infertilitytreatment. In fact, the board implied that at times it
mightbe necessary to create embryos with no intent to transferthem
to a woman. For the sake of safety, the results of newtypes of
procedures would have to be studied in the labora-tory before the
procedures were offered clinically. It wouldbe unethical to
transfer to a woman the embryos resultingfrom unvalidated novel
procedures.The EAB report elicited an outpouring of letters
oppos-ing embryo research, and its recommendations were
neverimplemented. When the EAB charter expired in 1980, asubsequent
board was not appointed, thus leaving no bodyto review proposals
for federal funding of IVF and embryoresearch. This situation
effectively created a moratorium onfederal funding in the United
States, though it did not affectresearch that was privately
funded.Public Policy in Other CountriesIt is not possible to review
all legislation and policy recom-mendations throughout the world,
but two early initiativesare of particular interest. They come from
countries thatshare a common law tradition with the United
States,Australia (Victoria), and the United Kingdom.AUSTRALIA
(VICTORIA). The earliest comprehensive legis-lation on reproductive
technologies was enacted in the Stateof Victoria, Australia in
1984. The Infertility (MedicalProcedures) Act addressed embryo
research by prohibitingresearch that might damage the embryo or
make it unfit forimplantation. This prohibition appeared to outlaw
any IVFor embryo research that was not directed toward
benefitingeach individual embryo.In 1986 the review committee
established by the actreceived a proposal for research on the
microinjection of asingle sperm into an egg. In their application
the investiga-tors suggested a novel approach for circumventing
theprohibition on embryo research. They proposed to examinethe egg
after the sperm had penetrated it, but before thegenetic
contributions of the sperm and egg had fused at thestage known as
syngamy. Arguing that fertilization was notcompleted until syngamy
had occurred, researchers claimedthat the law did not apply until
the time of syngamy, thusgiving them approximately twenty-two hours
after spermpenetration for conducting their studies.Since the
review committee was uncertain as to whetherthe 1984 act allowed
this interpretation, it recommendedthat the act be amended to
clarify that research was permissi-ble if it ended by the time of
syngamy, even if the researchdestroyed the embryos potential for
implantation. The actwas amended according to this recommendation
in 1987.UNITED KINGDOM. The issue of the regulation of
reproduc-tive technologies and embryo research was particularly
press-ing in the United Kingdom because of the publicity given
tothe birth of Louise Brown in England in 1978. The
WarnockCommittee was appointed to study the matter, and its
1984report recommended national regulation of assisted
repro-duction. It also recommended that research on
embryosresulting from IVF be permitted up to the fourteenth
dayafter fertilization, under the jurisdiction of a licensing
body.Based on the Warnock Report, the Human Fertilisationand
Embryology Act (HFE Act) of 1990 commissioned astanding body, the
Human Fertilisation and EmbryologyAuthority (HFEA), to develop
standards for licensing clini-cal facilities and research
protocols, and mechanisms forauditing and oversight. Initially
research protocols wererestricted to the study of infertility, the
causes of congenitaldiseases, and the detection of gene or
chromosome abnor-malities in embryos.Since its establishment in
1991 the HFEA has ad-dressed new types of procedures and research
through publicconsultation processes as well as the advice of
experts. If amatter was beyond the scope of authority of the HFEA,
itwas referred to Parliament. In January 2001 Parliamentextended
the HFE Act to permit embryo research directed atincreasing
knowledge about treatments for serious diseases.This provision
would allow the HFEA to issue licenses forresearch on embryonic
stem cells, including stem cellsderived from blastocysts resulting
from somatic cell nuclearreplacement (SCNR). However, the Pro-Life
Alliance broughta challenge to this provision, arguing that the HFE
Actapplied only to embryos resulting from the fertilization ofeggs
by sperm. Despite a Court of Appeal ruling against thePro-Life
Alliance, in June 2002 the House of Lords agreed tohear a final
appeal of the case. In March 2003 the House ofLords ruled that the
HFE Act applied to all types of embryos,and hence the HFEA had
authority over research withembryos created by nuclear transfer as
well as embryosresulting from fertilization by sperm.The U.S. Human
Embryo Research PanelAfter nearly twenty years of moratorium on
federal fundingof research involving IVF, the U.S. Congress in
1993revoked the requirement of EAB review. Through the
National Institutes of Health (NIH) Revitalization Act of1993,
Congress explicitly permitted the NIH to fund re-search on assisted
reproductive technologies with the goal ofimproving the
understanding and treatment of infertility.Since research on IVF
includes the study of IVF-fertilized embryos, the research
authorized by Congressincluded research involving human embryos.
Recognizingthe controversial issues raised by this research, NIH
decidedto conduct an examination of ethical issues before
fundingany research proposals. Consequently, the Director of
NIHappointed the Human Embryo Research Panel (HERP) toprovide
advice and recommendations.In developing its position and
recommendations, thepanel focused on two distinct sources of
guidance: view-points on the moral status of the early human
embryo, andethical standards governing research involving human
sub-jects. It considered a wide range of possible views on themoral
status of the embryo, from the position that fullhuman personhood
is attained at fertilization, to the argu-ment that personhood
requires self-consciousness and is notattained until after birth.
In the end, all nineteen members ofthe panel agreed to the
following statement:Although the preimplantation embryo
warrantsserious moral consideration as a developing formof human
life, it does not have the same moralstatus as an infant or child.
(Human EmbryoResearch Panel, p. x)This conclusion implied that the
preimplantation em-bryo is not a full human subject and thus is not
a fullyprotectable human being. As a result, some research
thatmight be destructive to the embryo could be acceptable
forfederal funding. But the panel also asserted that the
humanembryo warrants serious moral consideration, requiringthat it
be treated differently from mere human cells oranimal embryos. The
panel proposed restrictions on embryoresearch that would express
such moral consideration, forexample, that human embryos be used in
research only as alast resort, that the number of embryos used be
carefullylimited, and that embryos not be allowed to develop
longerthan required by a specific research protocol, and in no
caselonger than fourteen days of development.In applying the
ethical standards governing researchinvolving human subjects, panel
members invoked thecriteria used by Institutional Review Boards
(IRBs) inapproving research protocols. Donors of eggs, sperm,
orembryos were to be informed of the specific goals, proce-dures,
and risks of research projects. Risks to donors, par-ticularly egg
donors, were to be minimized. Eggs for researchcould be donated
only by women who were undergoingdiagnostic or therapeutic
procedures where egg retrievalwould present little additional
risk.The most controversial issue facing the panel was thequestion
of whether human oocytes could be fertilized solelyfor research
purposes. The panel decided to allow suchfertilization only under
very special circumstances, mostparticularly, if certain research
by its very nature could nototherwise be conducted. For example,
research on thelaboratory maturation of human oocytes, which could
elimi-nate the need for egg donors as well as infertile women to
besubjected to high levels of hormonal stimulation, requiresstudy
as to whether such oocytes can be successfully fertilized.The
panels limited acceptance of the fertilization ofoocytes for
research purposes aroused strong criticism, andPresident Bill
Clinton immediately announced his opposition.The Aftermath in the
United Statesand BeyondDespite President Clintons directive that
NIH not fundresearch involving the creation of embryos, most types
ofresearch on IVF and human embryos were still eligible forfederal
funding. However, in its next appropriations billCongress reversed
its previous stance and prohibited NIHfrom funding any research
that might involve damaging ordestroying human embryos. In 2003
this prohibition wasstill in effect.During the 1990s scientific
advances raised new ques-tions regarding research with human
embryos. In 1998 thefirst embryonic stem cell lines were developed
from the innercell mass of human blastocysts, and at the same time,
similarstem cell lines were produced from the germ cell tissue
ofaborted fetuses. Deriving stem cells from blastocysts wasclearly
prohibited for federal funding. However, the deriva-tion of stem
cells from the tissue of aborted fetuses waseligible for federal
funding under previous legislation (U.S.Public Law 10343,
Manier).Another discovery was the successful cloning of avariety of
nonhuman animals from adult cells, beginningwith the cloning of the
sheep Dolly in 1997. Research onhuman cloning arguably involves
research on human em-bryos. These embryos are produced by transfer
of somaticcell nuclei into enucleated oocytes, rather than
throughfertilization of eggs by sperm, yet their development
andpotential appear to be similar to those of fertilized eggs.
Thuscloning research raises similar ethical questions.The day after
the announcement of the cloning ofDolly, President Clinton
instructed the National BioethicsAdvisory Commission (NBAC) to
undertake a thoroughreview of the technology and to report within
ninety days.
Given this short deadline, it is understandable that NBAChad to
focus on issues specific to the cloning process. Inparticular, NBAC
decided to not revisit ... the issuessurrounding embryo research,
since the topic had recentlyreceived careful attention by a
National Institutes of Healthpanel, the Administration, and
Congress (Shapiro).In contrast, when the Presidents Council on
Bioethicsappointed by President George W. Bush issued its report
oncloning in 2002, it called for a broader debate on the
entiretopic of human embryo research. The ten-member majorityof the
council wanted cloning discussed in the propercontext of embryo
research in general and not just that ofcloning (p. 133). Both the
majority and minority reportscall attention to the fact that human
embryo research of alltypes remains essentially unregulated in the
private sector,with the minority noting that it seems inappropriate
to haltpromising embryo research in one arena (cloned embryos)while
it proceeds essentially unregulated in others (p. 143).In the
United States, public policy at the national levelis focused on
what types of research are eligible for publicfunding. There is
essentially no regulation of research in theprivate sector. This
situation contrasts sharply with that ofmost other countries, where
laws apply to all research,regardless of the funding source.As of
April 2003, Germany, Austria, and Ireland pro-hibit embryo research
unless intended to benefit the individ-ual embryo subject. Germany
does allow some importationof established stem cell lines for
research. France prohibitsany embryo research that would harm the
embryo. How-ever, in January 2002 the French assembly passed a bill
that,if enacted, would permit research using surplus
embryosoriginally created for reproductive purposes. Sweden
allowsresearch on surplus embryos up to day fourteen,
includingresearch on deriving stem cell lines. Creating IVF
embryossolely for research is prohibited, but creating embryos
throughnuclear transfer is not mentioned in Swedish law and thushas
an uncertain legal status. The United Kingdom arguablyhas the most
permissive policies on embryo research withinthe European Union. It
explicitly sanctions the granting oflicenses to create embryos,
including cloned embryos, forspecific research projects.Because of
the diverse views and policies of its memberstates, the European
Union has taken an intermediateposition, providing support for
research on surplus embryosin countries where that is permitted,
but discouraging thecreation of embryos for research. In April 2003
the Euro-pean parliament voted for a ban on cloning or
otherwisecreating embryos for stem cell research. However,
thisdecision becomes law only if approved by all fifteen
memberstates of the European Union.In May 2002 the Assisted Human
Reproduction Actwas introduced into the Canadian Parliament. The
actprohibits the creation of a human clone for any purpose. Italso
prohibits the creation of an IVF embryo for researchpurposes with
the exception of improving or providinginstruction in assisted
reproduction procedures. In April2003 the bill was in its third
reading in the House ofCommons.In some non-Western countries,
embryo research isproceeding with few restrictions. Chinese
laboratories areforging ahead with cloning research to develop stem
cells.Though Chinese scientists have been slow to publish
theirwork, they may well be ahead of their Western
counterparts(Leggett and Regalado). India has developed a number
ofinternationally recognized stem cell lines, and scientists
aredeveloping additional lines. Dr. Firuza Parikh, Director
ofReliance Life Sciences in Bombay, links their success to
theabsence of cultural and political opposition to embryoresearch
(Lakshmi).The Moral Status of the Early EmbryoIn contrast to China
and India, most Western countries aredeeply divided over ethical
issues related to embryo research.Does the embryo merit full
protectability from the momentof fertilization, or does it
gradually attain full protectabilityas it moves through a series of
developmental stages? Iffertilization is not the point of greatest
moral significance, isthere some later developmental marker beyond
which em-bryo research ought not be conducted?FERTILIZATION.
Fertilization of egg by sperm marks theinitiation of a new and
unique genotype, that of a humanbeing distinct from either of its
progenitors. The zygote orfertilized egg not only contains the plan
or blueprint for anew human being, but it has the potential within
itself todevelop into that human being.Based on these facts, many
would argue that the zygoteis a full human being from the moment it
comes intoexistence. This view would preclude any research that
mightbe harmful or destructive to an embryo, unless intended tobe
therapeutic for that embryo or to improve its chances
forimplantation. This position has received able defense
incontemporary terms by opponents of embryo research (Mc-Carthy and
Moraczewski).It is possible to hold this position while
acknowledgingthat fertilization is a process rather than an
instantaneousevent, and hence that the new human life begins only
whenthe process of fertilization is completed. At least two
possiblecandidates marking the completion of fertilization havebeen
suggested. The first is the time of syngamy, when the
chromosomes from the male and female gametes unite toform the
genotype of the embryo. Since syngamy is notcompleted until about
twenty-four hours after the spermpenetrates the egg, this view
would allow some study of theearly development of the embryo.A
second proposal maintains that the embryo does notbegin its life as
a new human being until the regulation of itsdevelopment switches
from oocyte genes to embryonicgenes. In 1988 Peter Braude and
colleagues showed that thisoccurs at the six- to eight-cell stage,
approximately two daysafter penetration of egg by sperm. Arguably
the embryobegins its own life distinct from that of the oocyte at
the timethat its own internal regulatory mechanism begins to
func-tion. This interpretation would allow investigation of
ques-tions such as why a large proportion of embryos are arrestedin
their development during the earliest cell divisions
(VanBlerkom).Such variant views of the process of fertilization do
notcounter the claim that the human being begins its life
atfertilization. Rather, they provide differing interpretationsas
to what constitutes fertilization, under the assumptionthat the
formation or activation of the unique genotype ofthe new organism
is the crucial event.IMPLANTATION. Implantation is the process by
which theembryo imbeds itself in the uterine wall and begins to
takenourishment from the woman, thus marking the beginningof
pregnancy. It is at this time that the U.S. federal regula-tions
define the product of conception as a fetus, and theresearch
regulations begin to apply (45 CFR 46.201207).From a moral point of
view, some have argued that theIVF embryo lacks the potential to
develop into a humanbeing as long as it is simply maintained in
culture in thelaboratory. Only those embryos that are transferred
towomen and that implant successfully acquire the potentialfor
development. This type of argument has been utilized bypoliticians
like U.S. Senator Orrin Hatch, who supportsome forms of embryo
research while they take pro-lifepositions in relation to abortion.
In his testimony to aCongressional subcommittee in July 2001, Hatch
stated, Ibelieve that a humans life begins in the womb, not in a
petridish or refrigerator.This view can be linked to a philosophic
distinctionbetween possible persons, entities that could possibly
developinto persons if certain actions were taken with respect
tothem, and potential persons, entities that will develop
intopersons in the normal course of events unless somethinghappens
or is done to interrupt that development. Theembryo in the
laboratory or freezer is a possible person thatmight develop into a
person if action were taken to transfer itto a uterus. The
already-implanted embryo or fetus is apotential person that, under
normal circumstances, willcontinue to develop into a person.
Proponents of thisdistinction argue that while we may have a moral
obligationnot to interfere with the development of a potential
person,we do not have a similar obligation to bring every
possibleperson into existence (Singer and Dawson; Tauer
1997a).PRIMITIVE STREAK. In the late twentieth century,
scholarswere faced with biological data about early
embryonicdevelopment that led to new perspectives on the
ontologicaland moral status of the early embryo. Particularly
within theCatholic tradition, writers such as Norman Ford,
JohnMahoney, Richard McCormick, and Karl Rahner developedarguments
questioning whether the zygote or early embryois a full human being
or human person. Their argumentsappealed to the following points:1.
Twinning of the embryo is possible until implanta-tion, and at
least through the morula stage, severalembryos may aggregate
(recombine) to form oneembryo. Thus the embryo lacks
developmentalindividuation at this early stage. Philosophic
ar-guments that rely on the continuity of per-sonal identity and
religious arguments based onensoulment must deal with the phenomena
oftwinning and recombination, which occur naturallyand can also be
induced scientifically.2. Until the blastocyst stage at
approximately five daysafter fertilization, the cells of the embryo
aretotipotent or completely undifferentiated. Each cellhas the
capacity to differentiate into any of the cellor tissue types of
the fetus, or more likely, not tobecome part of the fetus at all
but rather to formplacental and other extra-embryonic tissues.
Theearly embryo is a collection of undifferentiated cellsrather
than an organized individual.3. At approximately fourteen days
after fertilization, theprimitive streak appears, the groove along
themidline of the embryonic disk that establishes in theembryo its
cranio-caudal (head-to-tail) and left-rightaxes. The primitive
streak marks the beginning ofthe differentiation of cells into the
various tissuesand organs of the human body, and thus initiatesthe
development of the embryo proper (the cellsthat will become the
fetus) as an organized, unifiedentity. The primitive streak is also
the precursor ofthe neural system.In normal procreation, during the
period betweenfertilization and the completion of implantation
alarge proportion of embryos (generally estimated atover 50%) are
discarded naturally. Karl Rahnerargues that it is implausible that
such a largenumber of human beings could come into existence
and disappear without anyones knowing about it.Others have
argued that given natures prodigalitywith human embryos, it ought
to be morallyacceptable to allow similar types of embryonic
lossesin research as part of the effort to achieve
healthypregnancies.These sorts of arguments have been utilized in
publicpolicy debates since 1978, and the appearance of the
primi-tive streak has come to be accepted internationally as
amarker carrying moral significance. The prohibition ofembryo
research after fourteen days of development isalmost universally
accepted.Opponents of embryo research have responded toclaims that
the early embryo is not yet a full human being.These commentators
find arguments based on twinning andrecombination, totipotency of
cells, and embryo loss to beunpersuasive (Ashley; Ashley and
Moraczewski; Mirkes). Inits 2002 report on cloning, the majority
members of the U.S.Presidents Council on Bioethics questioned the
significanceof the primitive streak as a moral marker,
stating:Because the embryos human and individual ge-netic identity
is present from the start, nothingthat happens later ... at
fourteen days or anyother timeis responsible for suddenly
conferringa novel human individuality or identity. (p.
97)GASTRULATION AND NEURULATION. Some persons re-gard the
initiation of the neural system or the presence ofbrain activity to
be the most significant marker for thebeginning of the life of a
human being. This view is based onthe belief that the brain is the
essential organ underlying ourspecifically human capacities. It
also represents an effort toidentify a criterion at the beginning
of human life that isanalogous to the criterion of whole-brain
death marking theend of life. For those who regard the presence of
sentience asa necessary condition for personhood, the neural system
issignificant since sentience is impossible in the absence of
anyneural structures.While there is debate as to the stage at which
brainactivity first occurs, it is certain that there is no brain
activitybefore fourteen days of gestational age. The emergence
ofthe primitive streak marks the very beginning of the devel-opment
of the nervous system. If the presence of neuralstructures is the
significant criterion for the beginning of ahuman life, then it
might be permissible to extend embryoresearch slightly beyond
fourteen days of development.Several possible cut-off points have
been suggested. Bythe completion of gastrulation at about seventeen
days, thethree germ layers of the embryo are in place, with cells
ofeach layer committed to forming tissues and organs of one ofthree
types. Subsequent neural development leads to thebeginning of
closure of the neural tube around twenty-onedays, with the
primitive nervous system in place by thecompletion of neurulation
around twenty-eight days.However, given the widespread consensus
that fourteendays of gestational age is a morally defensible
boundary forembryo research, there has been limited discussion of
ex-tending research to a later embryonic stage.Other Moral
ConsiderationsThose who believe that the human embryo is a
fullyprotectable human being have no choice but to opposeembryo
research that could not ethically be performed oninfants or
children. But those who maintain that the earlyembryo is not yet a
full human being, still have to determinehow that embryo ought to
be treated.Some have proposed severely restrictive criteria
forembryo research. Norman Ford, after providing
painstakingarguments to support the conclusion that the embryo
can-not be a human individual until fourteen days after
fertiliza-tion, acknowledges that he could be wrong. In his view,
theCatholic Church is right to insist on the principle thathuman
embryos should be treated as persons, even if theymay not be (2001,
p. 160). In other words, as long as there isany degree of
uncertainty regarding the moral status of theembryo, it must be
absolutely inviolate.A more commonly held view is that the human
embryohas an intermediate sort of moral status. While it is not
afully protectable human being, it is not merely cells or
tissue.Proponents of this view are generally willing to permit
someembryo research with restrictions that acknowledge that
theembryo is nascent human life or a developing form ofhuman life.
Our ethical obligation toward the embryo isoften characterized as
respect or profound respect.Proponents as well as opponents of
embryo researchhave questioned the concept of respect as a guide
for humanembryo research. John Robertson, an advocate of
scientificfreedom with respect to embryo research, believes the
notionof respect carries mainly symbolic significance. Hence
itspractical ramifications are vague, potentially allowing a
widerange of types of research. Daniel Callahan, in an
essayopposing most embryo research, wonders how one showsrespect
for a living being while intending to end its life andfuture
potential, even if done for a good purpose such asresearch on
infertility or disease.In an effort to express respect for the
special status of thehuman embryo, public policy bodies have
stipulated condi-tions for embryo research that are considerably
more restric-tive than policies on research with human cells or
animal
embryos. For example, research must have important scien-tific
or medical goals and may involve human embryos onlywhen the
research cannot be conducted in any other way.Research projects
should be restricted to the smallest num-ber of embryos that is
feasible, and for the shortest possibletime period. Careful records
and security must be utilized toensure that no embryos are diverted
for unapproved pur-poses and that none are sold.Bringing Embryos
into Existencefor ResearchOne of the most contentious issues in
embryo ethics is thequestion of whether it is ever justifiable to
bring humanembryos into existence specifically for research
purposes.Many would argue that research use of surplus
embryosremaining after the completion of infertility treatment
isethically acceptable, since these embryos are destined to
bedestroyed in any case. At the same time, they may hold thatthe
development of embryos for research purposes, so-calledresearch
embryos, is not morally justified.The development of embryos for
research purposes hasbeen characterized as a novel practice that
requires particularjustification. Referring to embryos created
through nuclearcell transfer, the Presidents Council on Bioethics
in 2002claimed that such research creation of embryos
wouldconstitute crossing a major moral boundary (p. 132).
Yetdecades of research on human IVF beginning in the 1930srequired
investigation of various methods of laboratoryfertilization,
followed by study of cleaving fertilized eggs todetermine their
normality before transfer to a woman waseven considered (Soupart
and Strong; Edwards and Steptoe).Commentators agree that there is
no ontological orintrinsic distinction between surplus embryos
remainingafter infertility treatment and research embryos
developedspecifically for study. Arguments that support a
moraldistinction must identify other morally relevant factors.
Theconcept of respect is often invoked, as is the notion of
intent.Respect for the special status of the embryo seems torequire
that embryos be treated as entities of intrinsic value.When embryos
are created purely for research purposes, theybecome instruments
for purposes that have nothing to dowith the embryos themselves. In
Kantian terms, the embryosare used solely as means for the welfare
of others rather thanas ends in themselves. The practice of
creating researchembryos thus results in treating embryos as
commodities,equivalent to mere cells or tissues.In contrast, the
intent to procreate justifies the develop-ment of embryos in the
laboratory. Even when a largenumber of eggs is fertilized in an IVF
procedure, eachfertilized egg has an equal chance of being
transferred to awoman and developing into a human being. Thus
eachzygote is equally respected for its procreative potential.It is
only because some of the embryos cannot betransferred (because of
the decision of the progenitors, orbecause there simply are too
many of them) that theybecome surplus embryos and are destined for
destruction. Itis arguably permissible to derive some good from the
inevita-ble destruction of these embryos by using them in
research.In doing so, one may be said to be choosing the lesser
evil.These arguments have been countered by a number
ofconsiderations.It may be true that respect for the special status
of thehuman embryo requires that it be treated differently frommere
human tissue. But the concept of respect is vague andundetermined,
so that a wide range of concrete interpreta-tions is plausible. The
claim that respect precludes allcreation of research embryos gives
heavy weight to oneinterpretation of the concept at the expense of
any counter-vailing considerations. Research projects that include
thedevelopment of embryos may promise significant benefitsfor
relieving the suffering of living human beings. Thesebenefits could
outweigh a particular interpretation of respect.While procreative
intent may justify the creation ofembryos in the laboratory, it is
plausible that other sorts ofpurposes could provide equally valid
justifications. Thetreatment of infertility, an elective medical
procedure, mayeven hold lesser moral significance than the
development ofcures for life-threatening or significantly disabling
diseasesand trauma outcomes. Hence such goals may also justify
thecreation of embryos.Moreover, surplus embryos do not appear
purely bychance. Clinicians frequently make a decision to
fertilizelarge numbers of eggs in order to optimize the chances
ofestablishing a pregnancy. The initial intent is not to giveevery
zygote the opportunity for implantation, but to achieveone or more
pregnancies and births, as desired by theprogenitors. A later
decision to direct unused embryos toresearch cannot be justified by
the principle of the lesser evil,since the existence of surplus
embryos should have beenanticipated. This situation was
deliberately caused and couldhave been avoided. Thus it is invalid
to invoke the principleof the lesser evil to justify use of surplus
embryos in research,while maintaining that any creation of research
embryos isprohibited.ParthenogenesisA potentially non-controversial
process for developing morulasand blastocysts for research is the
activation of oocytes
without use of sperm or transfer of somatic cell nuclei.
Suchactivation can be achieved through electrostimulation
orchemicals in a process called parthenogenesis. The
resultingcleaving eggs, called parthenotes, may develop much
likenormal embryos at least to the blastocyst stage. Although
nohuman parthenotes have progressed this far, in February2002
scientists announced that they had developed monkeyparthenote
blastocysts and established stable stem cell linesfrom them
(Cibelli, et al.).Scientists believe there is a profound and
intrinsicbiological barrier that prevents mammalian parthenotesfrom
developing to advanced fetal stages (Human EmbryoResearch Panel, p.
20). On this assumption, parthenogenicmorulas or blastocysts lack
the intrinsic potential to becomehuman beings. If this potential is
a defining aspect of thehuman embryo and the basis for its special
moral status, thenhuman parthenotes are not human embryos and
should notarouse the same sorts of moral concerns. Thus they may
offeran attractive alternative for research.CAROL A.
TAUERSEEALSO:Abortion:MedicalPerspectives;Children:Healthcareand
Research Issues; Cloning; Feminism; Fetal Research;Infants;
Infanticide; Maternal-Fetal Relationship; MoralStatus; Reproductive
Technologies: Ethical Issues; ResearchPolicy: Risk and Vulnerable
Groups; Research, Unethical;and other Embryo and Fetus
subentriesBIBLIOGRAPHYAnnas, George J.; Caplan, Arthur; and Elias,
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Transplantation of Fetal Tissue.Available from .III. STEM CELL
RESEARCH ANDTHERAPYIn this entry we review the ethical and legal
issues that arisein the context of stem cell research and therapy.
Stem cellshave attracted both immense scientific interest and
equalethical and legal concern because of their capacity to
spe-cialize and become virtually any part of the organism intowhich
they are introduced. Thus if introduced into the brainthey become
brain cells, if into the cardiovascular systemthey become cells of
that type and so on. They also appear tobe able to trigger cell
regeneration and colonize damagedtissue effecting repair in situ.
Thus if such cells are madecompatible with the genome of a host
using cloning tech-niques they could in principle repair and
regenerate dam-aged tissue and halt or even cure many diseases.
This holdsout both great promise and causes great unease in
equalmeasure. Here we examine both the scientific promise andthe
extent to which ethical and legal safeguards may
beappropriate.Ethical IssuesThe ethical aspects of human stem cell
research raise a widevariety of important and controversial issues.
Many of theseissues have to do with the different sources from
which stemcells may be obtained. Stem cells are at present
obtainedfrom adults, umbilical cord blood, and fetal and
embryonictissue. Although there are widely differing views
regardingthe ethics of sourcing stem cells in these ways, there is
generalconsensus that embryos are the best source of stem cells
fortherapeutic purposesa consensus that may of course changeas the
science develops. If spare embryos or aborted fetusesmay be used as
sources for stem cells, there is a furtherquestion: Should embryos
or fetuses be deliberately pro-duced in order to be sources of stem
cells, whether or notthey are also intended to survive stem cell
harvesting andgrow into healthy adults?The European Group on Ethics
in Science and NewTechnologies, which advises the European
Commission, hashighlighted the womens rights issues involved in
stem cellresearch. It is particularly worth bearing in mind
thatwomen, as the most proximate sources of embryonic andfetal
material and hence also of cord blood, may be underspecial
pressures and indeed risks if these are to be thesources of stem
cells.The issue of free and informed consent, both of donorsand
recipients, raises special problems. Because embryos andfetuses can
hardly consent to their role in sourcing stem cells,the question of
who may give consent for the use of fetal orembryonic material is
important, particularly because theusual basis for parental consent
is hardly appropriate. Thisbasis involves a judgment about what is
in the best interestsof the individual, and because, in most cases,
the individualin question will not survive, the test is irrelevant
(Harris,2002a). Competent risk-benefit assessment is vital,
andparticular attention needs to be paid to appropriate
ethicalstandards in the conduct of research on human subjects.Other
issues concern the anonymity of the donors, thesecurity and safety
of cell banks, and the confidentiality andprivacy of the genetic
information and the tissue the bankscontain. Finally, there are
issues of remuneration for thosetaking part and of the transport
and security of human tissueand genetic material and information
across borders bothwithin the European Union (EU) and worldwide.
Whilethese issues are important, they are well understood
inbiomedical ethics, and with the exception of the issue ofconsent,
they do not raise special issues in connection withstem cell
research and therapy (U.K. Human GeneticsCommission).Before
considering the ethics of such use in detail, it isimportant to
first explore the possible therapeutic andresearch uses of stem
cells and also the imperatives forresearch and therapy.WHY
EMBRYONIC STEM CELLS? Embryonic stem cellswere first grown in
culture in February 1998 by James A.Thomson of the University of
Wisconsin. In November ofthat year Thomson and his colleagues
announced in thejournal Science that such human embryonic stem
cellsformed a wide variety of recognizable tissues when
trans-planted into mice. Roger A. Pedersen, writing in 1999,noted
potential applications of these stem cells:Research on embryonic
stem cells will ultimatelylead to techniques for generating cells
that can beemployed in therapies, not just for heart attacks,but
for many conditions in which tissue is damaged.If it were possible
to control the differentiation ofhuman embryonic stem cells in
culture the result-ing cells could potentially help repair
damage
caused by congestive heart failure, Parkinsonsdisease, diabetes,
and other afflictions. They couldprove especially valuable for
treating conditionsaffecting the heart and the islets of the
pancreas,which retain few or no stem cells in an adult and socannot
renew themselves naturally.Stem cells, then, might eventually
enable us to growtailor-made human organs. Furthermore, using
cloningtechnology of the type that produced Dolly the sheep,
theseorgans could be made individually compatible with
theirdesignated recipients. In addition to tailor-made organs
orparts of organs, such as heart valves, it may be possible to
useembryonic stem cells to colonize damaged parts of the
body,including the brain, and to promote the repair and regrowthof
damaged tissue. These possibilities have long been theo-retically
understood, but it is only now with the isolation ofhuman embryonic
stem cells that their benefits are beingseriously considered.Stem
cells for therapy. It is difficult to estimate howmany people might
benefit from the products of stem cellresearch should it be
permitted and prove fruitful. Mostsources agree that the most
proximate use of human embry-onic stem cell therapy would for
Parkinsons disease, acommon neurological disease that has a
disastrous effect onthe quality of life of those afflicted with it.
In the UnitedKingdom around 120,000 individuals have Parkinsons,
andthe Parkinsons Disease Foundation estimates that the dis-ease
affects between 1 million and 1.5 million Americans.Another source
speculates that the true prevalence ofidiopathic Parkinsons disease
in London may be around200 per 100,000 (Schrag, Ben-Shlomo, and
Quinn). Untoldhuman misery and suffering could be stemmed if
Parkinsonsdisease became treatable. If treatments become available
forcongestive heart failure and diabetes, for example, and if,
asmany believe, tailor-made transplant organs will eventuallybe
possible, then literally millions of people worldwide willbe
treated using stem cell therapy.When a possible new therapy holds
out promise ofdramatic cures, caution is of course advised, if only
todampen false hopes of an early treatment. For the sake of
allthose awaiting therapy, however, it is equally important
topursue the research that might lead to therapy with all vigor.To
fail to do so would be to deny people who might benefitthe
possibility of therapy.ImmortalityFinally we should note the
possibility of therapies thatwould extend life, perhaps even to the
point at whichhumans might become in some sense immortal.
This,albeit futuristic dimension of stem cell research raises
impor-tant issues that are worth serious consideration.
Manyscientists now believe that death is not inevitable that
thatthe process whereby cells seem to be programmed to age anddie
is a contingent accident of human development whichcan in principle
and perhaps in fact be reversed and part ofthat reversal may flow
from the regenerative power of stemcells. Immortality has been
discussed at length elsewhere butwe should, before turning to the
ethics of stem cell researchand therapy note one important possible
consequence of lifeextending procedures.Human Evolution and Species
ProtectionHuman Embryonic Stem Cell research in general, but
theimmortalizing properties of such research in particular
raisesanother acute question. If we become substantially
longerlived and healthier, and certainly if we transformed
ourselvesfrom mortals into immortals we would have changedour
fundamental nature. One of the common definingcharacteristics of a
human being is our mortality. Indeed inEnglish we are
mortalspersons; not immortals orGods, demi-gods or devils. Is there
then any moral reason tostay as we are simply because it is as we
are? Is theresomething sacrosanct about the human life form? Do
wehave moral reasons against further evolution whether it isnatural
Darwinian evolution, or evolution determined byconscious choice?One
choice that may confront us is as to whether or notto attempt
treatments that might enhance human function-ing, so-called
enhancement therapies. For example it maybe that because of their
regenerative capacities stem cellsinserted into the brain to repair
damage might in a normalbrain have the effect of enhancing brain
function. Again itwould be difficult if the therapies are proved
safe in the caseof brain damaged patients to resist requests for
their use asenhancement therapies. What after all could be
unethicalabout improving brain function? We dont consider
itunethical to choose schools on the basis of their
(admittedlydoubtful) claims to achieve this, why would a more
efficientmethod seem problematic?We should not of course attempt to
change humannature for the worse and we must be very sure that in
makingany modifications we would in fact be changing it for
thebetter, and that we can do so safely, without unwanted
side-effects. However if we could change the genome of humanbeings,
say by adding a new manufactured and syntheticgene sequence which
would protect us from most majordiseases and allow us to live on
average twenty five per centlonger with a healthy life throughout
our allotted time,
many would want to benefit from this. In high-incomecountries
human beings now do live on average twenty fiveper cent longer than
they did 100 years ago and this is usuallycited as an unmitigated
advantage of progress. The point issometimes made that so long as
humans continued to beable to procreate after any modifications,
which changed ournature, we would still be, in the biological
sense, members ofthe same species. But, the point is not whether we
remainmembers of the same species in some narrow biological
sensebut whether we have changed our nature and perhaps with itour
conception of normal species functioning.THE ETHICS OF STEM CELL
RESEARCH. Stem cell researchis of ethical significance for three
major reasons:1. It will for the foreseeable future involve the use
andsacrifice of human embryos.2. Because of the regenerative
properties of stem cells,stem cell therapy may always be more
thantherapeuticit may involve the enhancement ofhuman functioning
and indeed the extension of thehuman lifespan.3. So-called
therapeutic cloning, the use of cell nuclearreplacement to make the
stem cells clones of thegenome of their intended recipient,
involves thecreation of cloned pluripotent (cells that have
thepower to become almost any part of the re-sulting organismhence
pluri-potent)and possiblytotipotent cells (cells which have the
power tobecome any part of the resulting organism includingthe
whole organism), which some people findobjectionable.In other
venues, John Harris has discussed in detail theethics of genetic
enhancement (Harris, 1992, 1998a) andthe ethics of cloning (Harris,
1997, 1998b, 1999b). Thefocus of this entry, however, is on
objections to the use ofembryos and fetuses as sources of stem
cells.Because aborted fetuses and preimplantation embryosare
currently the most promising sources of stem cells forresearch and
therapeutic purposes, the recovery and use ofstem cells for current
practical purposes seems to turncrucially on the moral status of
the embryo and the fetus.There have, however, been a number of
developments thatshow promise for the recovery and use of adult
stem cells. Itwas reported in 2002 that Catherine Verfaillie and
her groupat the University of Minnesota had successful isolated
adultstem cells from bone marrow and that these seemed to
havepluripotent properties (capable of development in manyways but
not in all ways and not capable of becoming a newseparate
creature), like most human embryonic stem cellshave.
Simultaneously, Nature Online published a paper fromRon McKay at
the U.S. National Institutes of Healthshowing the promise of
embryo-derived cells in the treat-ment of Parkinsons disease.Such
findings indicate the importance of pursuing bothlines of research
in parallel. The dangers of abjuring embryoresearch in the hope
that adult stem cells will be found to dothe job adequately is
highly dangerous and problematic for anumber of reasons. First, it
is not yet known whether adultcells will prove as good as embryonic
cells for therapeuticpurposes; there is simply much more
accumulated dataabout and much more therapeutic promise for
embryonicstem cells. Second, it might turn out that adult cells
will begood for some therapeutic purposes and embryonic stemcells
for others. Third, whereas scientists have already dis-covered that
virtually any gene in embryonic stem cells canbe modified or
replaced, this has not yet been established tohold for adult stem
cells. Finally, it would be an irresponsiblegamble with human lives
to back one source of cells ratherthan another and to make people
wait and possibly die whilewhat is still the less favored source of
stem cells is furtherdeveloped. This means that the ethics of
embryonic stemcells is still a vital and pressing problem and
cannot for theforeseeable future be bypassed by a concentration on
adultstem cells.RESOLVING THE ETHICS OF RECOVERING STEM CELLSFROM
EMBRYOS. There are three more or less contentiousways of resolving
the question of whether it is ethicallypermissible to use the
embryo or the fetus as a source ofmaterial, including stem cells,
for research and therapy. Thethree methods involve: (1) solving the
vexing question of themoral status of the embryo; (2) invoking the
principle ofwaste avoidance; and (3) showing that those who profess
toaccord full moral status to the embryo either cannot
consis-tently do so or do not in fact believe (despite what
theyprofess) that it has that status. Regarding the first of these,
itis difficult to determine whether there will ever be
suffi-ciently convincing arguments available for this question tobe
finally resolved in the sense of securing the agreement ofall
rational beings to a particular view of the matter (Harris,1985,
1999a). Putting aside this contentious issue, then, theother two
issues will be discussed below.The principle of waste avoidance.
This widely sharedprinciple states th