Anyone who has been paying attention to public affairs knows that the United States and many other nations are grappling with two big bioethical issues: human embryonic stem cell research and human cloning. Although I have the honor to serve on the President's Council on Bioethics, the opinions I will express in this epilogue are my own, not those of the president, and certainly not those of the president's Council. While my personal views happen to be closely in line with those of President Bush, the fact is that the members of the Council are not of a single mind on these issues. The president has chosen to appoint to the Council people representing quite a wide spectrum of views--including views sharply at odds with his own.
First some background: Stem cells are primitive cells that are capable of forming diverse types of tissue. Because of this remarkable quality, human stem cells hold tremendous promise for the development of therapies to regenerate damaged organs and heal people who are suffering from terrible diseases.
Embryonic stem cells are derived from human embryos. Their use is controversial because, unfortunately, such stem cells cannot be harvested without destroying the living embryo. Other sources of stem cells are available, however, and can be harvested from umbilical cord blood as well as from fat, bone marrow, and other adult tissue without harm to the donor. An enormous amount of research involving adult stem cells is currently going on in laboratories in the United States. This research is ethically uncontroversial and has generated a number of exciting discoveries on the therapeutic front.
For many therapeutic purposes, adult stem cells are superior to embryonic stem cells because of their comparative stability. (In certain cases, adult stem cells are clearly preferable because of the risk that the use of volatile embryonic stem cells will cause tumors of various types.) However, no one knows with certainty whether adult stem cells can be obtained that possess the versatility or flexibility to do everything that embryonic stem cells hold out the promise of doing. Recently, Dr. Catherine Verfaille and co-workers at the University of Minnesota discovered "multipotent adult progenitor cells" in bone marrow that can, some have claimed, "differentiate into pretty much everything that embryonic stem cells can differentiate into," and, indeed, "turn into every single tissue in the [human] body." What remains to be seen is whether Dr. Verfaille's results can be replicated and her findings confirmed. It is possible, though by no means certain, that the debate over embryonic stem cell research can be obviated by the development of equally good (or even superior) alternatives that are ethically unproblematic.
President Bush's Decision on Stem Cell Funding
Because embryonic stem cell research involves the destruction of the embryos from whom stem cells are harvested, federal funding for it was banned by an act of Congress. The Department of Health and Human Services under President Clinton, however, reinterpreted the provisions of that act to permit the funding of research using stem cells harvested from embryos destroyed with private money. When President Bush came into office, he was faced with a decision whether to uphold the ban as originally understood or stick with the Clinton Administration's interpretation. In August, after a period of deliberation marked by intense lobbying and public relations campaigns by both sides, the president announced that he would not permit funding of research involving stem cells harvested from embryos destroyed in the future; he would, however, permit continued funding of research on existing cell lines derived from embryos from which stem cells had been harvested.
Some people hailed the president's decision as a principled compromise that maintained the norm against deliberate embryo destruction but allowed funding for research to continue where the embryos from which stem cells had been harvested were already dead and could not be restored to life. Other people on both sides of the question were, however, disappointed. Those in favor of embryonic research argued that too few good cell lines existed to enable scientists to fulfill what they asserted was the enormous and unique promise of embryonic stem cell research. As a result, they contended, many people would continue to suffer from horrible diseases that might be cured, or whose painful and damaging effects might be mitigated, by therapies and technologies deriving from embryonic stem cell research. People on the other side, while approving the president's ban on funding of research involving further embryo destruction, disagreed with his permission of funding for research on existing cell lines. They worried that this might down the line lead to further embryo killing; some went further, arguing that just as it would be wrong to make use of knowledge derived by unethical experimentation by German scientists in the Nazi period, it is unjust for people to make research use of material derived from the destruction of embryonic human beings.
But are they human beings? Here we reach the central question. It is also the question at the heart of the current debate over human cloning. Now, some readers may be surprised about that. Isn't cloning a matter of the asexual reproduction of human beings as genetic copies (or near copies) of other human beings? What does that have to do with the human status of embryos and the rightness or wrongness of destroying them?
Well, cloning is indeed the bringing into being by asexual processes genetic copies (or near copies) of existing beings. When, to international fanfare, Dolly the sheep was cloned a few years ago, here is how it was done. The nucleus of a somatic cell of an adult ewe was transferred to a sheep ovum (or oocyte) whose nucleus had been removed. Electrofusion was then employed to produce a distinct, self-integrating, new organism possessing the genome of the original ewe (of which Dolly could be considered a sort of younger twin). This organism--Dolly--developed from the embryonic, through the fetal and other stages of her development as an otherwise ordinary sheep, and into adulthood.
Now, in principle (some claim that it has already been done in fact) it should be scientifically possible to generate new human beings by the same procedure--a technique called Somatic Cell Nuclear Transfer. Some people think that this would be a good thing; most people do not.
Those who favor the reproduction of human beings by cloning argue that it would enable people to have a desirable control over the qualities and genetic characteristics of the children they have. They suggest that it would enable certain people who might otherwise not have children to have them. They say that it would make it possible for people who suffer the loss of a child to have the comfort of a genetic copy of the child. They maintain that cloning is a matter of "reproductive choice" and ought to be freely permitted.
Those who oppose the reproduction of human beings by cloning--I among them--insist that it is a dehumanizing procedure that will lead our culture down the road--or further down the road--to the commodification of human life. They argue that it constitutes treating children as products of manufacture--"made" rather than "begotten"--compromising their individuality and raising a knot of serious problems pertaining to kinship, identity, and self-image. They warn that it will exacerbate the difficulty children already have when parents become obsessive in their expectations for their children and seek to live vicariously through them.
This is an important debate; and someday we will almost certainly have it. Not now, though. There is overwhelming support in the public at large and in both houses of Congress for a ban on cloning human beings for reproductive purposes. Even many people who do not oppose what is called "reproductive cloning" as a matter of strict moral principle favor a ban for now. University of Chicago Professor Dr. Leon Kass, Chairman of the President's Council on Bioethics, sums up the reasons:
Any attempt to clone a human being would constitute an unethical experiment upon the resulting child-to-be. In all the animal experiments, fewer than two to three percent of all cloning attempts succeeded. Not only are there fetal deaths and stillborn infants, but many of the so-called 'successes' are in fact failures. As has only recently become clear, there is a very high incidence of major disabilities and deformities in cloned animals that attain live birth. Cloned cows often have heart and lung problems; cloned mice later develop pathological obesity; other live-born cloned animals fail to reach normal developmental milestones.1
As if to confirm Dr. Kass's concerns, we were recently informed that Dolly the sheep has been diagnosed with a severe and premature arthritis.
So across the spectrum people oppose cloning for baby-making, at least for now. But that does not mean that everybody opposes cloning as such. Many people favor legislation that would ban human cloning for reproductive purposes but permit it for purposes of biomedical research. This position has been endorsed by the National Academy of Sciences and a number of other groups. Commonly, cloning for biomedical research purposes is called "therapeutic" cloning, though that language is controversial. I myself reject the term "therapeutic" in this connection because the cloning in question is not for the benefit of the embryo brought into existence by it. In fact, that embryo will be destroyed. So, the President's Council, seeking a morally neutral term, refers to it as "research cloning"--a label that can be accepted by supporters and critics alike. Here, the procedure of Nuclear Somatic Cell Transfer is used to create an embryo that will be used for research and in the process destroyed rather than implanted in the prepared uterus of a woman and permitted to develop into a fetus, infant, child, adolescent, and adult.
There are significant scientific and potential therapeutic advantages (though not, of course, to the cloned embryos themselves) to research cloning. In particular, in the area of regenerative medicine there is the possibility of harvesting material from embryonic clones that, because of the nearly perfect genetic match to the patient, will not be prone to rejection. Anyone familiar with transplantation surgery, for example, knows that rejection is the great bane of the field. Suppressing the human immune system to prevent rejection of implanted organs is difficult, dangerous, and all-too-often unsuccessful. If cloning could help to solve the problem, it would be a genuine leap forward. It is little wonder that people who do not have moral objections to the deliberate destruction of human embryos are very excited about the promise of research cloning.
But then again, it is little wonder that those who do oppose the deliberate destruction of human embryos find research cloning particularly appalling. Critics contend that it constitutes bringing new human beings into existence precisely for the purpose of killing them and harvesting their body parts. This, they say, is the ultimate in the commodification of human life and the dehumanization of man in the name of scientific progress. Worse yet, if this is combined with a ban on implanting these embryos in women's wombs--a ban designed to prevent the "reproductive cloning" that almost everybody opposes--it creates a bizarre state of affairs:Society would permit new human beings to be brought into existence but forbid people from doing what is necessary for them to survive and grow. In effect, the law would define a class of developing human beings that it is illegal not to discard or destroy. Since what would be banned, strictly speaking, would be implantation rather than cloning itself, it would amount to legally mandated human embryo destruction.
Now, all of this should make clear why it is that the question of the humanity of the embryo is central not only to the debate about embryonic stem cell research but also to the debate about human cloning. If human embryos are not human beings, then (1) the promise of advances in scientific knowledge, (2) the prospect of developing useful therapies, and (3) the general principle of liberty of scientific inquiry would make an overwhelming case for funding research involving embryo destruction. If, however, human embryos are human beings, then the case for a ban on funding destructive embryo research--and, indeed, a ban on the research itself--would be powerful. To dislodge it, advocates of the research would have to show either that the deliberate killing of some human beings to benefit others can be justified by some sort of utilitarian calculus; or they would have to demonstrate that human beings do not have a right to life throughout their existence, but acquire such a right only at some point in their development.
Are Somatic Cells Equivalent to Embryos?
Those who argue that human embryos are not human beings point out that the five or six-day-old embryo is very small--smaller than the period at the end of a sentence on a printed page. It looks nothing like what we ordinarily think of as a human being. It has not yet developed a brain--so it does not exhibit the human capacity for rationality. Indeed, it has no consciousness or awareness of any sort. It is not even sentient. Of course, people who deny that human embryos are human beings acknowledge that the entities in question possess a human genome. They point out, however, that the same is true of ordinary somatic cells such as the skin cells millions of which each of us rubs or washes off our bodies on any given day. Plainly these cells are not human beings; nobody supposes that there is anything wrong with destroying them or using them in scientific research.
In defending research involving the destruction of human embryos, Ronald Bailey, a science writer for Reason magazine, has developed the analogy between embryos and somatic cells in light of the possibility of human cloning. Bailey claims that every cell in the human body has as much potential for development as any huma n embryo. Embryos therefore have no greater dignity or higher moral status than ordinary somatic cells. Bailey observes that each cell in the human body possesses the entire DNA code; each has become specialized (as muscle, skin, etc.) by most of that code being turned off. In cloning, those portions of the code previously de-activated are re-activated. So, Bailey says, quoting Australian bioethicist Julian Savulescu: "If all our cells could be persons, then we cannot appeal to the fact that an embryo could be a person to justify the special treatment we give it." Since plainly we are not prepared to regard all of our cells as human beings, we shouldn't regard embryos as human beings.
What do opponents of embryo destruction say in reply to these points and arguments? To claims about the size and appearance of the embryo, they observe that it merely begs the question about the humanity of the embryo to say that it does not resemble (in size, shape, etc.) human beings in later stages of development. The five-day old embryo looks exactly like what human beings look like at five days old. Each of us once looked like that. The morally relevant consideration is not appearance; rather, it is the fact that from the beginning the embryo possesses the epigenetic primordia for self-directed growth and maturation through the stages of human development from the embryonic, through the fetal, infant, child, and adolescent stages, and into adulthood with its distinctness and identity fully intact. As such, the embryo is a whole, living member of the species homo sapiens which is already--and not merely potentially--developing itself (actually himself or herself since sex is already determined) to the next more mature stage along the continuum of development of a determinate and enduring human life.
The point was illustrated rather vividly at the second meeting of the President's Council on Bioethics at which we had a presentation by, and discussion with, Dr. Irving L. Weissman, chairman of the committee of the National Academy of Sciences that drafted the recent report on human cloning. Dr. Weissman, one of the nation's most distinguished research scientists and a leader in the field of adult stem cell research, personally favors funding of embryonic research as well as cloning for research purposes. He was with us, however, to answer scientific questions, and (as he made very clear) not to offer opinions on ethics, a subject matter in which he claims no particular expertise. He was very candid with us, and informative. Let me paraphrase our exchange. I asked Dr. Weissman whether the chairman of the President's Council, Dr. Leon Kass, who was presiding at the meeting, is as a matter of fact the same human being who, at an earlier stage of his development, was an adolescent and before that an infant. "Yes," Dr. Weissman replied. " And before that was he in the fetal stage of his development?" "Yes." "And before that"--at this point Dr. Weissman was under no illusions about where this line of questioning was heading--"was he in the blastocyst stage?" "For sure." "When we speak of 'the blastocyst' (or 'the embryo'), then, we are referring not to a being or entity different or distinct from the 'human being'; we are referring rather to a developmental stage?" "Right."
But if this is true, one might ask, wouldn't we have to conclude by the same train of logic that an adult who came into existence by a process of cloning from a human skin cell was once a skin cell (just as Leon Kass--like all the rest of us--was once an embryo), and that skin cells are therefore nascent human beings? Ronald Bailey's argument in the form reductio ad absurdum was designed to show that those who hold for the humanity of the embryo are driven to this obviously false conclusion. However, Bailey's analogy between somatic cells and human embryos collapses under scrutiny. The somatic cell is something from which (together with other causes) a new organism can be generated; it is certainly not, however, a distinct organism. A human embryo, by contrast, already is a distinct, self-developing, complete (though immature) human organism.
Bailey suggests that the somatic cell and the embryo are on the same level because both have the "potential" to develop to a mature human being. The kind of "potentiality" possessed by somatic cells that might be used in cloning differs profoundly, however, from the potentiality of the embryo. In the case of somatic cells, each has a potential only in the sense that something can be done to it so that its constituents (its DNA molecules) enter into a distinct whole human organism, which is a human being, a person. In the case of the embryo, by contrast, he or she already is already actively--indeed dynamically--developing himself or herself to the further stages of maturity of the distinct organism--the human being--he or she already is. True, the whole genetic code is present in each somatic cell; and this code can be used for guidance of the growth of a new entire organism. But this point does nothing to show that its potentiality is the same as that of a human embryo. When the nucleus of an ovum is removed and a somatic cell is inserted into the remainder of the ovum and given an electric stimulus, this does far more than merely place the somatic cell in an environment hospitable to its continuing maturation and development. Indeed, it generates a wholly distinct, self-integrating, entirely new organism--indeed, it generates an embryo. The entity--the embryo--brought into being by this process, is quite radically different from the constituents that entered into its generation.
Somatic cells, in the context of cloning, then, are analogous not to embryos, but to the gametes whose union results in the generation of a distinct, self-integrating, new organism in the case of ordinary sexual reproduction. Sperm cells and ova are not distinct, complete, self-integrating human organisms; they are properly speaking parts of human organisms--the men and women whose gametes they are. Their union can generate a new organism, an entity that is not merely part of another organism. That organism was never, however, a sperm cell or an ovum. Nor would a person who was brought into being as an embryo by a process of cloning have been once a somatic cell. Dr. Kass and you and I, as Dr. Weissman made clear, were once embryos, just as we were once children, and before that infants, and before that fetuses. But none of us were ever sperm cells, or ova, or somatic cells. To destroy an ovum or a skin cell whose constituents might have been used to generate a new and distinct human organism is not to destroy a new and distinct human organism--for no such organism exists or ever existed. But, in line with Dr. Weissman's logic, for someone to have destroyed the human being who is now you or me during the embryonic stage of our existence and development would have been to destroy you or me.
Or would it have been? After all, Dr. Kass and you and I really are remarkably different today than we were as embryos. We have developed and changed in profound ways. Perhaps we are the same organism that existed then, but perhaps we were at that stage of our development not yet persons--that is, human beings with dignity and rights, including a right to life. Perhaps we acquired dignity and rights not by merely coming into existence, but by developing certain qualities, or capacities, or traits. In fact, perhaps you and I were never really embryos; perhaps you and I are not the physical, material realities that come into being by fusion of gametes or by cloning, but are rather the psychological or spiritual realities--the "centers of consciousness"--somehow associated with our material bodies but distinct from them. Perhaps I am not the physical organism you see before you and hear speaking. Perhaps I did not come into existence until sometime after that organism (which I merely inhabit or with which I am somehow otherwise associated) came into existence; and perhaps I may cease to be before my physical body dies (for example, by going into a permanent coma or persistent vegetative state).
Michael Gazzaniga, a member of the President's Council who favors embryo research is a distinguished brain scientist at Dartmouth College. He argues that the human person comes into being with the development of a brain and that prior to that point we have a complete human organism, but one lacking the dignity and rights of a person. Human embryos may therefore legitimately be treated as we would treat organs available for transplantation (assuming, as with transplantable organs, that proper consent for their use was given, etc.). In developing his case, Dr. Gazzaniga observes that modern medicine treats the death of the brain as the death of the person--authorizing the harvesting of organs from the remains of the person, even if some physical systems are still functioning. But if a human being is no longer a person with rights once the brain has died, then surely a human being is not yet a person prior to the development of the brain.
Critics, however, and again I am one, call attention to a damning defect in this argument. Under prevailing law and medical practice, the rationale for " brain death" is not that a brain-dead body is a living human organism but no longer a person. Rather, brain death is accepted because the irreversible collapse of the brain destroys the capacity for self-directed integral organic functioning of human beings who have matured to the stage at which the brain performs the key role in integrating the organism. What is left is no longer a unitary organism at all. Obviously, the fact that an embryo has not yet developed a brain (though its capacity to do so is inherent and active, just as the capacity of an infant to develop its brain sufficiently for it to actually think is inherent and active) does not mean that it is incapable of self-directed integral organic functioning. Unlike a corpse--which is merely the remains of what was once a human organism but is now dead, even if particular systems may be mechanically sustained--a human being in the embryonic stage of development is a unified, self-integrating human organism. It is not dead, but very much alive. A factor or factors other than the brain make possible its self-integration and organic functioning. Its future lies ahead of it, unless it is cut off or not permitted to develop its inherent capacities. Thus it is that I and other defenders of embryonic human life insist that the embryo is not a "potential life" but is rather a life with potential. It is a potential adult, in the same way that fetuses, infants, children, and adolescents are potential adults. It has the potential for agency, just as fetuses, infants, and small children do. But, like human beings in the fetal, infant, child, and adolescent stages, human beings in the embryonic stage are already, and not merely potentially, human beings. All of these stages are, as Dr. Weissman made clear, developmental stages in the life of a being who comes into existence as a single cell human organism and develops, if all goes well, into adulthood by a gradual and gapless process over many years. An embryo (or fetus or infant) is not something distinct from a human being; it is a human being at the earliest stage of its development.
But what about the possibility that I mentioned a few minutes ago that we are not really our bodies anyway; we are centers of consciousness--minds, or souls, or what have you--inhabiting bodies or somehow, perhaps mysteriously, associated with them. If this is true, then it is not enough for defenders of embryonic life to prove that embryos are whole living members of the species homo sapiens; that the embryonic stage is simply the earliest stage of the development of a distinct and determinate organism; and that that organism in the embryonic stage is directing its own integral organic functioning as it develops itself into and through the next more mature stage on the continuum of a human life.
Well, this conception of the human being as a nonbodily person who inhabits and uses a nonpersonal body--a conception known in the philosophical literature as "person/body dualism"--moves us into deep metaphysical waters. It presents a clear alternative to the view of the human being as a dynamic unity of body, mind, and spirit. Is it sound?
The separation of "person" and "body"--the conception of the body as a subpersonal instrument rather than as a part of the personal reality of the human being--is at the heart of the liberal secularist worldview. It is person/body dualism, I suggest, that underwrites orthodox liberal positions on "life issues" such as abortion and euthanasia, as well as on issues of marriage and sexual morality. Oxford University philosopher John Finnis has summed up the case against person/body dualism:
[It] suffers the fate of every account of our being, life, and activity which treats human person and human life, or conscious self and human organism, or acts of the human organism and acts of the person, as other and other. That fate is: to overlook, or render inexplicable, a unity which we know more intimately and thoroughly than any other unity in the world, indeed the very paradigm (for us) of substantial unity and identity through time. For this dualism renders inexplicable the unity (and continuity) in complexity, which one is aware of in each of one's conscious acts. Every dualism undertakes to be a theory of something (of my personal identity as a unitary and subsisting, intermittently self-conscious and freely self-directing organism), but ends up unable to pick out any one something of which to be the theory.
People--you and I and everybody else--are (whatever else we are) essentially human, physical organisms. The person that is writing these words is not an unseen consciousness somehow inhabiting the physical organism sitting at the word processor; I am, rather, a unified rational-animal organism. It is not that I--considered as something apart from the organism--have an organism; it is that I am a rational animal organism. Therefore, I--that is the human being, the person I am--came to be precisely when the animal organism I am came to be. I did not come to be first and then become a person later; nor will I cease being a person without ceasing to be (by dying).
Some people admit that human beings are (whatever else we are) physical organisms, and so concede that you and I once were embryos and fetuses, but argue, nonetheless, that we became intrinsically valuable (and bearers of a right to life) only at some point in time after we came to be, when we acquired some characteristic such as mental functioning, consciousness, or self-awareness. They believe that human beings are valuable in a sense that makes it wrong to kill them not in virtue of the kind of entity (i.e., the "substance") they are, but in virtue of some accidental characteristic--some quality or attribute that they may (or may not) acquire (and may eventually lose).
A serious problem with this view is that the characteristics or qualities it proposes as necessary for moral worth and a right to life all come in varying degrees. So the following questions naturally arise: What degree of the characteristic or quality is required? Can the answer to that question be anything other than arbitrary? Aren't people who have the characteristic or quality to a greater degree more valuable than people who have it to a lesser degree? What then of the principle of the equality of persons?
These questions begin to suggest the central flaw in this position. If it is an accidental characteristic or quality that provides moral worth and a right to life--if it is not enough to be a substantial entity with a rational nature, as all human beings are--then the characteristic or quality will have to be a capacity for mental functions of some sort. It will have to be a capacity because obviously one cannot say that certain living human beings who are not now performing mental functions (because they are asleep, for example, or in a reversible coma) are not "persons" who possess intrinsic value and a right to life. It will have to be a capacity for mental functions of some sort because persons (on any account of the matter) are distinguished from entities that are not persons by some sort of relation to mental functions (such as reasoning and acting on the basis of deliberation and choice). But human beings even in the embryonic, fetal, and infant stages have real capacities for mental functions, though not immediately exercisable.
The human embryo (or fetus or infant) possesses the capacity for such functions in virtue of the kind of entity he or she is, namely, a human being. Of course, the basic, natural capacity possessed by the embryo, fetus, infant, and in some respects even the toddler is not the capacity to exercise certain mental functions now in response to some stimulus. But even in the embryonic stage, the human being possesses the entirety of the positive reality needed actively to develop himself or herself to the point at which the basic natural capacity for the mental functions characteristic of human beings will be immediately exercisable. Indeed, the full development of the basic natural capacity for mental functioning is a process that will not be complete for many years. It will gradually develop as the human being matures through gestation, infancy, childhood, and adolescence and into adulthood. (Indeed, even in those human beings who due to injury, retardation, or some other misfortune will not develop the capacity fully or even very far, the capacity itself is present.)
The development of the basic natural capacity of human beings for their characteristic forms of mental functioning is, then, a matter of degree. The difference between the adult and the child, or the child and the embryo, is merely the gradual development of the same basic natural capacity. But the difference between how we should treat a person (i.e., a being who has intrinsic value and a right to life) and how we may treat an entity that is not a person, and may therefore legitimately be used and even destroyed for the benefit of persons, is a difference that can be morally justified only in virtue of a difference in kind between the person and the nonpersonal entity. Mere differences of degree cannot bear the moral weight required to justify treating some beings possessing the capacity (e.g., normal adults or adolescents) as having dignity and rights while treating other beings possessing the capacity in a lesser, or less developed, degree (e.g., human beings in the embryonic, fetal, or infant stages, mentally retarded people, victims of dementia or Alzheimer's disease) as lacking dignity and a right to life.
I conclude from the foregoing analysis that it is illegitimate to deny dignity and a right to life on the basis of age, size, stage of development, or condition of dependency, just as it is illegitimate to deny dignity and a right to life based on race, sex, ethnicity, or any other morally irrelevant factor. Because human beings in the embryonic, fetal, and infant stages do not differ in kind from more mature human beings, but differ only in such morally irrelevant factors as age, size, stage of development, and condition of dependency, they are equally entitled to legal protection and may not legitimately be reduced to the status of mere means to benefit others.
Of course, it flies in the face of strong "intuitions" that some people have that, say, a single cell human zygote, even conceding that it is a human being at the earliest stage, is not--cannot be--the equal in moral worth of an infant and even an adult human being. People who possess these intuitions observe that we typically do not mourn and hold funerals for embryos that die. Indeed, they point out, even in natural sexual reproduction upwards of half of all pregnancies fail naturally--often before women even know they are pregnant; we do not treat the deaths of these embryos as we would the loss of infants.
Defenders of embryonic life reply that reason, not emotion, must control ethical judgments--particularly where fundamental rights are concerned. It is perfectly understandable that the early embryo would not elicit from us the sympathy of more fully developed human beings--particularly in circumstances in which people with whom we do sympathize (because we emotionally regard them as "more like us") stand to benefit from their destruction.2 It was, no doubt, ever thus in human affairs. Progress in civilization comes, however, from moving beyond reliance on imagination and sense impressions and the emotions they generate--particularly in respect to who is "like" and "unlike" us--to the rational understanding of who truly is a human being and in that crucial respect "like us." Whether or not we feel the need to mourn for a particular human being--or a particular class of human beings--is not the criterion of their worth, dignity, and right to life. No one who recognizes and honors the rights of another need feel any guilt for failing to feel a need to mourn his death--especially where, either as a contingent matter or in the nature of the case, opportunities of forming emotional attachments did not present themselves.
How about the fact that large numbers of embryos die in natural failures of pregnancy? Does this mean that it is reasonable to treat human embryos as research material? The problem with this argument is that its principle would seem to lead to perverse results when applied in other contexts. Up until a little more than a century ago, infant mortality rates from natural causes were very high. In some times and places they were as high as embryonic deaths in pregnancy failures are today. (This is true even if we count all pregnancy failures as involving the deaths of true embryos. In fact, there is evidence that in many cases early pregnancy loss is the result of failures in conception and the resulting formation of entities possessing a human genome but lacking the epigenetic primordia for maturation as human beings, e.g., hydatidiform moles.) It would be absurd to conclude that in these circumstances human infants are not human beings and that they can therefore be destroyed for the purpose of harvesting organs for the benefit of others.
There is one more argument sometimes advanced by advocates of embryonic stem cell research and research cloning. While conceding that the human embryo is a complete human organism, they claim that in the early stages it is not really a human being because it is not a human individual. Why not? Because up until approximately fourteen days, it may divide into identical twins. Up until the point at which monozygotic twinning is no longer possible, they argue, the embryo is properly understood as a mere mass of cells--each cell totipotent (i.e., capable of becoming a complete individual) but independent of the others.
It is certainly true that at the earliest stages a cell or cells detached from the whole can develop into a complete organism. But it is fallacious to infer from that fact that before detachment the cells of the human embryo constitute merely an unintegrated, and thus incidental, mass. Just as separated parts of a flatworm have the potential to become a whole flatworm when isolated from the present whole of which they are a part, separated parts of the embryo at the earliest stages of development before specialization by the cells has progressed very far, can become whole and distinct embryonic human beings. No one supposes that the possibility of producing separate flatworms by dividing a single creature means that flatworms that could be separated, but have not been, are anything other than unitary individual organisms. Similarly, it would be wrong to suppose that the totipotency of the early embryo means that it is other than a distinct, unitary, complex, actively self-integrating, human organism--a developing human being.
Patrick Lee has made the following points in reply to the claim that the early embryo is a mere mass of totipotent cells:
From the very beginning, even at the zygote stage, the cells of the new organism are cytoplasmically and positionally differentiated. In mammals, even in the unfertilized ovum, there is already an "animal" pole (from which the nervous system and eyes develop) and a "vegetal" pole (from which the future lower organs and the gut develop). After the first cleavage, the cell coming from the "animal" pole is probably the primordium of the nervous system and the other senses, and the cell coming from the "vegetal" pole is probably the primordium of the digestive system. Moreover, the relative position of a cell from the very beginning (that is, from the first cleavage) does make a difference in how it functions. Again, most (identical) twinning occurs at the blastocyst stage, in which there clearly is a differentiation of the inner cell mass and the trophoblast that surrounds it (from which the placenta develops).
Lee goes on to observe that if the cells within the human embryo prior to twinning were each independent of the others, as the argument under consideration presupposes, then each would be expected to develop on its own. But that is not what happens.
Instead, these allegedly independent, non-communicating cells regularly function together to develop into a single, more mature member of the human species. This fact shows that interaction is taking place between cells within the zona pellucida, restraining them from individually developing as whole organisms and directing each of them to function as a relevant part of a single, whole organism continuous with the zygote. Thus, prior to an extrinsic division of the cells of the embryo, these cells together do constitute a single organism, and twinning is a phenomenon biologically equivalent to cloning.
It seems to me rationally undeniable that human embryos are, from the beginning, human beings with inherent dignity and rights. Having reflected as carefully as I can on the arguments advanced by those who would license embryo destruction for research purposes, I do not believe that their position can be morally justified. I understand, appreciate, and share their desire to advance scientific knowledge and produce new therapies; like them, I want to see science move ahead wherever it ethically can, adding to the sum of human knowledge and enhancing human health. The great moral principle of respect for the equal dignity of every human being places limits, however, on what we can do to some for the benefit of others. It forbids our treating living human beings at any stage or in any condition as exploitable and expendable "research material."
This speech was delivered at the Library of Congress in Washington on April 17, 2002, commemorating FRC's new publication: Building a Culture of Life: A Call to Respect Human Dignity in American Life.