Regarding Zygotes as Persons: Implications for Public Policy
Wall, L. Lewis, 1950Brown, Douglas.
Perspectives in Biology and Medicine, Volume 49, Number 4,
Autumn 2006, pp. 602-610 (Article)
Published by The Johns Hopkins University Press
DOI: 10.1353/pbm.2006.0065
For additional information about this article
http://muse.jhu.edu/journals/pbm/summary/v049/49.4wall.html
Access Provided by Brigham Young University at 02/10/11 5:25PM GMT
Regarding Zygotes
as Persons
implications for public policy
L. Lewis Wall* and Douglas Brown †
ABSTRACT In this paper, we examine the notion put forward by certain groups
(largely as a consequence of their opposition to elective abortion) that the immediate
post-fertilization cellular entity—the zygote—is a person and should be given full
moral status. Because the zygote has none of the inherent characteristics necessary to
be regarded as a person in the traditional philosophical sense (e.g., John Locke or Immanuel Kant), some advocates of this position attempt to advance their case with arguments based on the genetic potential of the human zygote to develop into a person.
We argue that this position represents a flawed use of human genetics and ignores the
extraordinarily inefficient and wasteful nature of human reproduction.We then explore
the public policy consequences that would follow from granting the zygote full moral
status.We conclude that the logical consequences of granting the zygote full moral status would require a revolutionary restructuring of many basic social institutions, especially the health care system.The social, political, and economic changes that would be
required if the zygote is enshrined as a person in law constitute a convincing reductio
ad absurdum that demonstrates the danger in taking this position seriously.
have reported numerous cases in which pharmacists have refused to fill prescriptions for emergency postcoital contraception such as Plan B (Davey 2005; Stein 2005).The reasons usually given for such
I
N RECENT MONTHS, newspapers
* Departments of Obstetrics-Gynecology and Anthropology,Washington University, St. Louis, MO.
† Center for Ethics and Humanities in the Life Sciences, Michigan State University, Lansing, MI.
Correspondence: L. Lewis Wall, Department of Obstetrics and Gynecology, Campus Box 8064,
Washington University School of Medicine, 660 South Euclid Avenue, Saint Louis, MO 63110.
E-mail: [email protected].
Perspectives in Biology and Medicine, volume 49, number 4 (autumn 2006):602–10
© 2006 by The Johns Hopkins University Press
602
Regarding Zygotes as Persons
objections are that Plan B and similar postcoital contraceptives cause the early
post-fertilization zygote to abort.The body of evidence concerning the mechanisms of action of such postcoital contraceptives overwhelmingly suggests that
these medications work by interfering with ovulation (particularly the LH
surge), rather than by disrupting the post-fertilization process (ACOG 2005;
Croxatto, Ortiz, and Muller 2003; Croxatto et al. 2001; Durand et al. 2001). Because a pregnancy does not by definition begin until the blastocyst implants in
the uterus (Code of Federal Regulations 2001; Hughes 1972; Schenker and Cain
1999), these drugs cannot be abortifacients.The pregnancy they are intended to
prevent does not yet exist at the time the drugs are taken. Moreover, Plan B and
similar postcoital contraceptives do not lead to an increase in congenital malformations if they are taken by a woman who already has an established, implanted
pregnancy (Bracken 1990).
Those who oppose the use of postcoital contraceptives such as Plan B argue
that such distinctions are mere semantic quibbles.They counter that, even granting the point that an abortion technically occurs only if an implanted blastocyst
is disrupted, uniquely human life still begins at fertilization; therefore, anything
that causes the demise of early zygotic life or interferes with its progression
toward viability constitutes an abortion in the broadest moral sense of the word,
irrespective of the technical details. By arguing in this way, those who hold this
view attempt to endow the pre-implantation embryo with a moral status equivalent to that of a developed fetus, a child, or even a fully functioning adult
human being.They argue that from the moment an egg is fertilized by a sperm
it possesses a “full human genetic package” and, therefore, having the potentiality
to develop into an adult, it is already a person. For this reason, they conclude that
the pre-implantation zygote is entitled to the full protection of the law, just as
any other person would be. Increasingly, advocates of this position seek to
impose their views on the medical profession and on society at large by enshrining these views in law, both at the state and federal levels.Within the context of
the debate about “emergency contraception,” of course, these views are irrelevant, because the clinical evidence indicates that Plan B and similar postcoital
contraceptives work by inhibiting ovulation (and, therefore, by preventing fertilization), rather than by interfering with a zygote. Misinformation on this topic
is commonplace, but tenaciously held, by the pro-zygote lobby.
Viewing the zygote as a full human person is not original to the 21st century;
rather, it is a reincarnation of an older biological viewpoint called preformationism: the belief that each individual egg or sperm contained an entire “preformed” person whose only task was to grow larger through the period of gestation. In preformationism’s most concrete and highly developed form, a human
gamete was thought to contain a tiny homunculus or “little man” who merely
expanded in size throughout pregnancy to become a newborn baby (Dombrowsky and Deltete 2000; Milby 1983;Walters 1997).This view, which was popular
in the 17th century, is the microscopic version of “the man in the moon.” As
autumn 2006 • volume 49, number 4
603
L . L e w i s Wa l l a n d D o u g l a s B r o w n
with belief about the man in the moon, the belief that there is a tiny homunculus in the human gamete arose due to the poor quality of the instruments used
by early scientific observers.When early microscopists looked at a human sperm
cell, they could not clearly see the nucleus. As a result, their imaginations told
them that the little smudges before their eyes must be tiny human beings waiting to take up residence in a human womb. Although this belief arose through
scientific error, it was nonetheless eagerly embraced by certain theologians and
has been promulgated into our time by succeeding generations of religious
thinkers long after this view was abandoned by biologists (Dombrowsky and
Deltete 2000). It is only a short step, intellectually speaking, from viewing
gametes as homunculi to viewing the zygote in a similar way. This article explores the implications for public policy in the United States if the view that a
zygote is a person were carried to its logical conclusions.
Are Zygotes “Persons”?
The first (and perhaps the most difficult) part of arguing that the zygote is a person lies in defining just what is meant by person. In the Western tradition of moral
philosophy, to be considered a person means that one is regarded as a moral
agent, as an individual worthy of moral consideration and respect on his or her
own terms, and as one who is capable of performing morally considerable actions. Perhaps the most influential philosophical definition of person is the definition given by the English philosopher John Locke in his 1690 Treatise on
Human Understanding. Locke defined person as “a thinking intelligent Being, that
has reason and reflection, and can consider itself as itself, the same thinking thing
in different times and places” (Book 2, chap. 27, p. 188). Similarly, a century later
the German philosopher Immanuel Kant argued personhood was synonymous
with the ability to exercise moral agency; that is, to be a person one had to be a
rational being who was able to comprehend the nature of the universal moral
law and to act according to its maxims (Kant 1785). If personhood requires consciousness and the exercise of free will, then by definition neither a zygote nor
a fetus before the middle of the third trimester at the very earliest is a person,
since the minimal anatomic and neurophysiological prerequisites for conscious
life have not yet developed.There is no evidence to suggest that a fetus exercises
any meaningful free will (Lee et al. 2005).
If we are to regard a zygote as a person, then, we must do so on the basis of
some other property or characteristic than those suggested by Locke or Kant.
Those who argue that the zygote is a person use a genetic criterion to make this
claim.They regard personhood as a property that comes along with a particular
genome.Thus Noonan (1970) could write: “The positive argument for conception as the decisive moment of humanization is that at conception the new being
receives the genetic code. It is this genetic information which determines his
604
Perspectives in Biology and Medicine
Regarding Zygotes as Persons
characteristics, which is the biological carrier of the possibility of human wisdom, which makes him a self-evolving being. A being with a human genetic
code is man” (p. 57).
The Problem of Defining
“Personhood” Genetically
From a philosophical perspective, terms such as the “human genome” or the
“human genetic package” sound more scientific than talking about “the soul.”
However, terminology of this kind is only superficial window-dressing unless the
meaning is defined precisely and specified in detail. Although some theologians
might find Noonan’s level of discourse persuasive, molecular biologists and
human geneticists are unlikely to find it so. Modern biochemistry and molecular genetics are far too scientifically advanced now to accept a vague “black box”
notion of personhood as being consubstantial with the human genome. If the
prerequisite for personhood is in fact having a human genome, those who argue
this point must define precisely what they understand the requisite human
genetic code for personhood to be. The genetic details must be clear and specific, otherwise this strategy is only a bad attempt to cloak a vague argument
with pseudoscientific terminology.
If personhood is inextricably intertwined with the contents of the human
genome, then this association ought to be a major area of human genetic research. If the minimal prerequisite for human personhood is simply the union of
human gametes, then gestational trophoblastic disease—both in its noncancerous
form as a hydatidiform molar pregnancy and in its aggressively malignant version as choriocarcinoma—are human persons, and the surgical operations and
chemotherapy used to kill such tumors are acts of homicide (Bedate and Cefalo
1989). If we are to allow a genetic definition of personhood to stand, those who
advocate this position must be able to tell us what specific characteristics of the
human genome constitute the minimal prerequisites for personhood.
If the human genetic package required for personhood means having a
46,XX or 46,XY karyotype, then women with Turner’s syndrome (45, X0),
Down’s syndrome (trisomy 21), or any of a large number of other non-lethal
chromosomal abnormalities are not human persons because they have an imperfect human karyotype—that is, their genetic makeup is something other than
46,XX or 46,XY. If an attempt is made to get around this problem by specifying that a genetic package somewhat less than a 100% of a normal human chromosomal definition is allowable—say 98% of a normal human genotype—then
we must be exceptionally careful to write our genetic definition of human personhood in such a way that we do not inadvertently include within this category other nonhuman primates such as chimpanzees and bonobos whose
genetic composition is 98.5% identical to that of humans, or we must be pre-
autumn 2006 • volume 49, number 4
605
L . L e w i s Wa l l a n d D o u g l a s B r o w n
pared to accept them as our moral brothers and sisters and grant them personhood too, as some writers have suggested (Cavalieri and Singer 1994; Chimpanzee Sequences and Analysis Consortium 2005; Gibbons 1998).
If personhood means the presence of other multifaceted potentialies for
development, then those who hold this position must specify just what those
potentialities are and, if they are to make the genetic argument, they must specify where in the human genome the biological substrates of those potentialities
reside.Without clear specifications as to exactly what constitutes genetic personhood, any line of demarcation drawn on the human genome is both arbitrary
and insufficient for the task it is being asked to perform. The genetic package
argument is clearly insufficient as the criterion for what constitues personhood.
We cannot slip zygotes into the category of persons using this mechanism without seriously damaging the category in other ways that are unacceptable.
The Wasteful Nature of Human Reproduction
Beyond this definitional problem, a further difficulty with arguing that zygotes
should be treated as persons lies in the extraordinarily inefficient and wasteful
nature of human reproduction. Many of those who hold genetic or preformationist views of personhood operate under the erroneous assumption that there
is a linear pathway between fertilization and childbirth, along which zygotes can
march in an uninterrupted parade. Noonan (1970), for example, wrote that once
fertilization has occurred “the chances are about 4 out of 5 that this new being
will develop” (1970, p. 56). Using this statistic, he argued that biological probabilities are of enormous significance in establishing the importance of fertilization as the defining moment for the realization of personhood:
The argument from probabilities is not aimed at establishing humanity but at
establishing an objective discontinuity which may be taken into account in
moral discourse. As life itself is a matter of probabilities, as most moral reasoning
is an estimate of probabilities, so it seems in accord with the structure of reality
and the nature of moral thought to found a moral judgment on the change in
probabilities at conception.The appeal to probabilities is the most commonsensical of arguments, to a greater or smaller degree all of us base our actions on
probabilities. . . .Would the argument be different if only one out of ten children
conceived came to term? Of course this argument would be different.This argument is an appeal to probabilities that actually exist, not to any and all states of
affairs which may be imagined. (p. 56)
Noonan’s logic in this passage was correct, but unfortunately for his argument,
his biology was wrong. The probabilities are exactly the opposite of what he
assumed in this passage: rather than a zygote having a four out of five chance of
surviving to term, the odds are closer to four out of five that a zygote will abort
spontaneously due to lethal genetic abnormalities that are manifested in early
606
Perspectives in Biology and Medicine
Regarding Zygotes as Persons
development (Chard 1991; Hertig and Rock 1973; Hertig et al. 1959; Macklon,
Geraedts, and Fauser 2002; Roberts and Lowe 1977).As Noonan acknowledged,
this drastic revision of our understanding of early pregnancy as a precarious and
highly tentative phenomenon does indeed change the nature of the argument.
As knowledge of the physiology of human reproduction has improved (thanks
in no small measure to the dramatic advances made in in vitro fertilization and
assisted reproductive technologies during the 20th century), it has become clear
that the vast majority of human fertilizations in vivo die before ever reaching
fetal viability.A conservative estimate suggests that at least 75% of all human fertilizations fail to advance to the point of viability, with the vast majority of such
failures occurring prior to the development of a clinically recognizable pregnancy (Chard 1991; Macklon, Geraedts, and Fauser 2002; Roberts and Lowe
1975). Approximately 30% of fertilized oocytes are lost before they even reach
the uterus, and another 30% either fail to implant or shrivel up and die shortly
after implantation. Most women in whom these events occur are unaware that
they are even taking place. Finally, an additional 15% abort spontanously during
the early first trimester, shortly after they have become clinically recognizable. In
light of these biological facts, the wisdom of granting the zygote full moral personhood seems extremely questionable.
Policy Consequences of Regarding
Zygotes as “Persons”
But, for the sake of argument, let us grant the zygote full moral status and regard
it as the moral equivalent of any normal, functioning, reasoning adult member
of society. What consequences would follow? For obstetricians, this posture
would change the definition of pregnancy. For example, if a woman were to undergo in vitro fertilization and successfully produce a zygote, her doctor would
be justified in charging her for prenatal care as soon as a zygote was created,
whether or not it was ever transferred to her body or implanted in her uterus
(Grimes and Raymond 2003). Not only that, but as a person a zygote kept
frozen in a storage locker would be fully entitled to inherit its parents’ property
should they die, and because zygotes would be persons in the eyes of the law, a
couple could claim an income tax deduction for every zygote in a reproductive
biology storage freezer.
Consider further the explosion in civil litigation and criminal prosecutions
that could result if legal personhood were extended to the zygote and early embryo. Since each zygote or embryo would be a person in the eyes of the law,
every spontaneous abortion or miscarriage would have to be regarded as a
potential homicide and investigated as such. Every woman with a positive pregnancy test could be required to produce evidence that she was still pregnant, or
be held accountable for the whereabouts and well-being of the conceptus. Since
zygotes, blastocysts, and early embryos would be legally entitled to sue for real
autumn 2006 • volume 49, number 4
607
L . L e w i s Wa l l a n d D o u g l a s B r o w n
or potential damages, every employer could reasonably argue that women of
reproductive age should be required to undergo monthly pregnancy tests as a
condition of employment to insure that embryonic and zygotic safety standards
were met in the workplace.
As stunning as such social changes would be, however, they would pale in
comparison to what such a policy would do to the health care system. Because
75% of human conceptions die spontaneously before reaching viability, there are
three times as many zygotic, embryonic, and fetal deaths each year as there are live
births. If each of these lost fertilizations has the same moral status as an adult
human being, the economic, social, and political consequences that logically follow from this premise would require a cataclysmic reorganization of health care
services. There were 4,091,063 live births in the United States in 2003, the last
year for which full statistics are available (Hamilton, Martin, and Sutton 2004).
In addition, approximately 20–25% of pregnancies in the United States are terminated by elective abortion (853,485 legal abortions occurred in 2001; Strauss
et al. 2004).Taken together, this would mean that approximately 4.8 million fertilization events reach clinical plausibility in the United States each year. Since
there are three times as many embryonic losses as there are viable pregnancies,
this means that over 14.5 million preclinical zygotic, embryonic, and fetal deaths
occur each year.There are only about 2.4 million total deaths of infants, children
and adults in the United States annually. On simple utilitarian grounds alone, if
we accord the newly conceived zygote the same moral status as a child or an
adult, taking this position mandates a massive redistribution of health care resources in the United States. If we accept the personhood of a newly fertilized
ovum, then the zygote, the morula, the fragile blastocyst, and the newly implanted embryo should become the central focus of our national health care system, and the rest of us must step to the back of the line.To do otherwise would
be both hypocritical and morally indefensible—if zygotes have the same moral
status as the rest of us.
Conclusion
We detect no public outcry to rearrange our national priorities in the way that
assigning personhood to the zygote would require.We are unaware of any critic
of postcoital contraception who seriously advocates such a radical refiguring of
our national priorities—and with good reason: they would be laughed off the
public stage in derision. This scenario, by itself, is telling. Although the pre-implantation embryo is worthy of being granted some moral status as an incipiently
developing biological entity, no one who argues the human zygote should have
equivalent moral status to a third trimester fetus, a child, or an adult is willing to
enact the public policies that logically follow from this premise.
Human pregnancies occur in the bodies of women.The pregnant state is one
in which there is a necessary and enormously complex interaction between the
608
Perspectives in Biology and Medicine
Regarding Zygotes as Persons
blastocyst-embryo-fetus and the woman in whose body this entity is devel-oping.
As the capabilities of the fetus to become a person increase, it makes intuitive
sense that the moral consideration given to the developing pregnancy also increases. However, irrespective of this increasing (but not yet full) moral considerability of the embryo/fetus, the women in whom such pregnancies develop are
already full moral agents themselves whose personal needs and values must trump
consideration of the developing zygote. Pregnancy is a unique (and particularly
in its earliest stages, an extremely fragile and precarious) state in which a half-foreign biological invader is permitted by the pregnant woman to take up temporary residence in her uterus until such time as it is expelled during the process of
labor (McDonagh 1996). It is the moment of birth that most clearly defines the
arrival of each unique individual into the human social community (Bermudez
1996). Granting fully equivalent rights to the zygote does not make moral sense,
would undermine the rights of women as full moral agents themselves, and would
have catastrophic implications for public policy.This is not a proposal that should
be implemented. It is not even a policy that deserves serious consideration.
References
American College of Obstetricians and Gynecologists (ACOG). 2005. Practice Bulletin
69. Emergency Oral Contraception. Dec. 2005.Washington, DC: ACOG.
Bedate C. A., and R. C. Cefalo. 1989.The zygote: To be or not be a person. J Med Philos
1989;14:641–45.
Bermudez, J. L. 1996.The moral significance of birth. Ethics 106:378–403.
Bracken, M. B. 1990. Oral contraception and congenital malformations: A review and
meta-analysis of the prospective studies. Obstet Gynecol 76:552–57.
Cavalieri, P., and P. Singer, eds. 1994. The Great Ape project: Equality beyond humanity. New
York: St. Martin’s Griffin.
Chard, T. 1991. Frequency of implantation and early pregnancy loss in natural cycles.
Baillieres Clin Obstet Gynaecol 5:179–89.
Chimpanzee Sequences and Analysis Consortium. 2005. Initial sequence of the chimpanzee genome and comparison with the human genome. Nature 437:69–87.
Code of Federal Regulations. 2001. Title 45. Public Welfare. Department of Health and
Human Services, National Institutes of Health, Office for Protection from Research
Risks, Part 46. Protection of Human Subjects, revised Nov. 13, 2001. Section 46.202.
Definitions 46.202(f).
Croxatto, H. B. 2001. Mechanism of action of hormonal preparations used for emergency
contraception: A review of the literature. Contraception 63:111–21.
Croxatto, H. B., M. E. Ortiz, and A. L. Muller. 2003. Mechanisms of action of emergency
contraception. Steroids 68:1095–98.
Davey, M. 2005. Illinois pharmacies ordered to provide birth control. NY Times, April 2.
Dombrowsky, D. A., and R. Deltete. 2000. A brief, liberal, Catholic defense of abortion. Urbana: Univ. of Illinois Press.
Durand, M., et al. 2001. On the mechanism of action of short-term levonorgestrel administration in emergency contraception. Contraception 64:227–34.
autumn 2006 • volume 49, number 4
609
L . L e w i s Wa l l a n d D o u g l a s B r o w n
Gibbons, A. 1998.Which of our genes makes us human? Science 281:1432–34.
Grimes, D. A., and E. G. Raymond. 2003. Emergency contraception: In response. Ann
Intern Med 138:238.
Hamilton, B. E., J. A. Martin, and P. D. Sutton. 2004. Births: Preliminary data for 2003.
Natl Vital Stat Rep 53(9):1–20.
Hertig, A.T., and J. Rock. 1973. Searching for early fertilized human ova. Gynec Invest 4:
121–39.
Hertig, A.T., et al. 1959.Thirty-four fertilized human ova, good, bad, and indifferent, recovered from 210 women of known fertility: A study of biologic wastage in early
human pregnancy. Pediatrics 23:202–11.
Hughes, E. C., ed. 1972. Obstetric-gynecologic terminology. Philadelphia: F. A. Davis.
Kant, I. 1785. Groundwork of the metaphysics of morals, ed. M. Gregor. Cambridge: Cambridge Univ. Press, 1998.
Lee, S. J, et al. 2005 Fetal pain: A systematic multidisciplinary review of the evidence.
JAMA 294:947–54.
Locke, J. 1690. An essay concerning human understanding, ed. A.S. Pringel-Pattison. Oxford:
Clarendon Press, 1924.
McDonagh, E. L. 1996. Breaking the abortion deadlock: From choice to consent. New York:
Oxford Univ. Press.
Macklon, N. S., J. P. Geraedts, and B. C. Fauser. 2002. Conception to ongoing pregnancy:
The “black box” of early pregnancy loss. Human Reprod Update 8:333–43.
Milby, T. H. 1983. The new biology and the question of personhood: Implications for
abortion. Am J Law Med 9:31–41
Noonan, J. T. 1970. An almost absolute value in history. In The morality of abortion: Legal
and historical perspectives, ed. J.T. Noonan, 1–59. Cambridge: Harvard Univ. Press.
Roberts, C. J., and C. R. Lowe. 1975.Where have all the conceptions gone? Lancet 1:498–
99.
Schenker, J. G., and J. M. Cain. 1999. FIGO committee for the ethical aspects of human
reproduction and women’s health. Int J Gynecol Obstet 64:317–22
Stein, R. 2005. Pharmacists’ rights at front of new debate because of beliefs, some refuse
to fill birth control prescriptions. Washington Post, March 28.
Strauss, L. T., et al. 2004. Abortion surveillance: United States, 2001. MMWR Surveill
Summ 53(SS-9):1–32.
Walters, J.W. 1997. What is a person? An ethical exploration. Urbana: Univ. of Illinois Press.
610
Perspectives in Biology and Medicine