Stem Cells

Human Cloning

Dianne N. Irving, M.A., Ph.D.
Professor of Philosophy
Dominican House of Studies
Washington, D.C. 20017

In March 1996, the news of the birth of a fatherless sheep affectionately named “Dolly” shocked the world. The possibility that human beings could be cloned too – long the subject of jokes and science fiction – began to awaken an inner fear. A rush of commentaries, conferences, and even Congressional debates followed – attempts to grapple responsibly with ethical, social and legal implications before the technology sweeps us toward some dark abyss.

Oddly, little public focus has been given to three central issues underlying the cloning debates: First, the scientific question, i.e., the exact physical nature and scientific status of the immediate product of cloning; second, the related philosophical question of “personhood”, and the ethical grounds for regulating cloning research; and third, the legal question concerning possible bans on cloning.

The scientific question should be answered by human embryologists, the scientists who have the required expertise and competency. At what point during the cloning process does a human being or human embryo physically come into existence? The answer to this scientific question, after all, should ground all of the other questions.

Yet answers to the scientific question emerging in the debates have revealed a prevailing inclination to avoid the verdict of human embryologists by the clever use of word games. For example, in “clarifying” remarks before a recent Congressional hearing, Rep. Henry Waxman (D-CA), echoing the position of many self-appointed bioethicists and others in the pharmaceutical industry, “explained” in effect that the immediate product of cloning is only a group of cells with two significant “potentials”. First, it is a “potential human being”, and only becomes an actual human being (and embryo) if it is implanted in a womb. Second, it is a “potential source of biological research material.” So, as long as it is not implanted, it could be ethically used to cure diseases and advance scientific knowledge.

What?? The immediate product of human cloning would not already be a whole, existing human being? Where have they been? Such “definitions” involve a very clever misuse of human embryological terms – an eerie echo of bioethics “language games” which have run rampant over the last 30 years. These games may be fun for bioethicists, philosophers, theologians and science fiction writers so inclined, but they are not the basis for sound public policy decision making.

The specious term “potential” applied to a human being and embryo, and the “logic” it implies (i.e., if it is not yet a human being or embryo, then we can use it for medical cures and great causes, etc.), derives from the now fully discredited term “pre-embryo.” It is a scientific myth – concocted by bioethicists, who for years used the term to justify and rationalize human embryonic and fetal research; supposedly the “only” way to find the cure for many diseases. “Pre-embryo” has also been used in debates about abortifacients and abortion, invoking similar confusion as to when a “person” begins – and thus “delaying” the human rights and protections due every human being. If in reality there is no such “delay,” public protection for all human beings could be brought earlier. But by obfuscation and techno-babble, the clarity of the science has become entangled with various philosophical constructs, precluding much-needed sound public policy decisions on cloning, and more broadly, on human embryo research as well.

The real issue in cloning concerns its immediate product. Although cloning and fertilization are different processes of human reproduction, the immediate product of both processes is the same! It might surprise many that there has been an unaltered scientific consensus for half a century that a real, already existing, live, whole human being begins as a human embryo (or zygote) immediately at fertilization. This is a scientific fact – not an “opinion,” or a religious or theological belief. And public policy debates and decision making should not continue to escape that unavoidable scientific fact. The same is true for cloning. The immediate product of cloning is physically the same – an already existing human being in embryo form.

But just what is “cloning”? Cloning is any of several techniques which may produce a new single cell female member of a species. For example, in the “somatic cell nuclear transfer” technique, the nucleus of a mature specialized cell (e.g., a skin cell) is made “unspecialized” by new techniques which restore the instructive potential of the full complement of chromosomes in the nucleus. The intracellular DNA messages which have selectively “silenced” the majority of chromosomes in the cell which are not relative to skin functions, are reversed.

The “unspecialized” nucleus is then transferred to a recipient egg cell (ovum – from the same or another member of the species) from which the nucleus has been removed. The resulting single combination of parts of 2 cells is then artificially chemically or electrically stimulated and commences activity as a new member of the species.

If cloning is done with human cells and succeeds, the donor cell would have 46 chromosomes in the nucleus, the number specific to human cells, and the resulting embryonic human being can continue to divide and develop.

To better understand this scientific fact, it might be helpful to compare the process of cloning with that of fertilization in normal human reproduction. Normal human pregnancy begins at fertilization when a male sperm and a female ovum, each containing 23 chromosomes, and neither of which is a human being, unite to form a single-cell human being (or zygote) with 46 chromosomes – the number specific for every member of the human species. As in cloning, a radical change in natures has taken place. A sperm and an ovum have changed from being individual gametes (parts of a whole human being) to something quite different, a whole, existing, unique human being. This change in natures is scientifically verified because of the extremely different kinds of functions and activities it performs which only a complete human being can do.

Looking closely at this “zygotic” human being or embryo, we know that it is already a girl or boy, and that he/she is genetically different from his/her mother or father. This tiny girl or boy (we will refer only to the girl for convenience) is quite a marvel. She is totipotent, i.e., this single-cell can produce all of the different kinds of cells a bigger, more complex human being ever needs. She contains all the genetic information needed for all the processes of her growth and development. Under her own direction, this tiny single-cell human zygote immediately produces specifically human proteins, enzymes – and soon specifically human tissues and organs (not cabbage or giraffe ones). This is accomplished by turning her genes on and off as needed by continually blocking and unblocking the genetic information in the DNA – thus sending a “cascade” of molecular information throughout her growth and development. Her development, then, does not involve a change of nature – as does fertilization or cloning – but is rather simply a physically continuous process of growth and complexity, which continues until death.

Lets watch this little girl grow! Generally the “embryonic period” extends from the single-cell zygote formed at fertilization (or cloning) to the end of the eighth week, during which she is called an “embryo.” Next, the “fetal period” extends from the ninth week to birth – during which she is called a “fetus.”

After fertilization, as the single-cell human zygote travels along the fallopian tube, she begins to divide asynchronously; e.g., first into 2 cells, then one of those cells divides, giving 3 cells, then the other divides, giving 4 cells, continuing on in staggered fashion. About the fourth day the growing embryo begins to compact into two layers (now called a blastocyst) as she enters the uterus. By the fifth day, the outer protective membrane begins to disintegrate so that she can implant into the uterine wall at about 5-7 days (called implantation). At about 14 days, the embryo begins to form three layers with the formation of the primitive streak – the beginning of the nerve net, future brain and spinal cord. By three weeks the heart begins to beat, the major divisions of the brain appear, as well as beginnings of the spinal cord, internal ears, eyes, face, body cavity and skeleton. By five weeks, the face is continuing to take shape, forehead, eyes, nostrils and mouth are evident, external ears are beginning, and hand and foot plates appear in limb buds.

This provides some context for a closer look at the distorted understanding of the developing human being in the earliest weeks, since most of the misinformation and misunderstanding in the cloning debates centers on this early period of growth. The discussion has been confused by the use of the now-discredited term “pre-embryo” and the incorrect science (often “frog” rather than “human” embryology) used to describe it – and its relevance to the “personhood” arguments.

In earlier bioethics debates on human fetal research, the term “pre-embryo” was coined by theologian Richard McCormick, S.J., and Clifford Grobstein – a frog embryologist. They acknowledge that there is a human being prior to 14 days, but agree that there is no human individual there yet (and therefore no “person” there yet), because before 14-days it may become twins (two individuals). Also, they say, only the inner layer of the 4-7 day blastocyst will become a human adult, because its outer layer is “all discarded” after birth. Therefore, they assert, before 14-days there is only a “pre-embryo,” or a “pre-implantation embryo” (a “potential person”); after 14-days twinning cannot take place, and only then is there definitely an “individual,” and therefore an existing “person” entitled to ethical and legal rights and protections. Congressman Waxman here takes an extra miss-step and denies there is a human being or embryo during this period.

The term “pre-embryo” has already been rejected by human embryologists as “inaccurate and unscientific,” according to Ronan O’Rahilly, one of the international “deans” in this scientific discipline. O’Rahilly developed the “Carnegie” stages which classify human embryology, and he sits on the international board (Nomina Embryologica), which determines the terminology to be used in this field. In his book, the leading text on human embryology, he repudiates the term “pre-embryo.” Others have also have brought it under criticism, and lately its use is avoided, though the damage has been done. What was meant to be conveyed – that the product of fertilization or cloning is not yet a human being or embryo, and therefore it is OK to use it for biological research material, or even cloning – is still too naively accepted.

One also now hears substitute phrases such as “pre-implantation embryo” (the embryo up to implantation at 5-7 days), or claims that “the human embryo does not begin until two weeks (sometimes three weeks) after fertilization”. Whatever arbitrary label is used, the aim is to convince us that there is only a “potential” human being or embryo there. But these claims are scientifically and absolutely wrong.

As already stated, the authoritative scientific conclusion is that a human embryo is a human being, beginning at fertilization (or cloning). In response to McCormick and Grobstein’s “frog science”, it is a scientific fact that, unlike frogs, human embryos do not divide synchronously, and the two layers of the blastocyst are in fact interactive. Nor are all the cells of the outer layer discarded after birth; in fact some of the blood cells and tissues of the adult human being are derived from that outer layer. The whole blastocyst is a human being, not just the inside part.

The twinning argument, supposedly “delaying” personhood for 14 days, is likewise scientifically flawed. It proves too much; twinning can take place after 14-days. It is a straw-man argument. In identical twinning, one individual human being (the early human embryo) divides, asexually. (As involving asexual reproduction, there is some analogy to cloning.) Thus from one individual, another individual splits off, resulting in two individuals (twins). The second twin is physically continuous with the original individual embryo which has split, and which also continues as an individual.

McCormick and Grobstein also use other unfounded science in their arguments, but these are the major mistakes. Since the science they use to ground their position is wrong, their “scientific” conclusion that before 14-days there exists only a “loose collection of cells” called a “pre-embryo”, a “pre-person”, is also wrong. Similarly, any implication that before 14-days, or before implantation, there exists only a “pre-human being” is also wrong. Scientifically, a human being and embryo begins immediately at fertilization or cloning; after that, there is no point along the continuous line of human embryogenesis where only a “potential” human being can be posited.

Any philosophical conclusion, legal opinion, or political agenda cannot escape this objective scientific fact. There can be no such thing as a “pre-embryo” or a “pre-person”, other than as an illusion in someone’s prejudiced or self-serving thinking. Yet efforts continue to co-opt and corrupt the actual scientific facts to fit them into someone’s philosophical, theological or political presuppositions. “Markers” – which are admittedly arbitrary, e.g., implantation, 14-days, brain formation, post-birth – will continue to appear in these debates.

“When does a human person begin?” is essentially a philosophical question, not a scientific one. Several “ways to go” in these debates have long been offered by bioethicists – all building on wrong science in order to expand the time-frame for interventions, experimentation and “treatments.” Most of the “philosophy” used is faulty as well. Some, using a sort of Cartesian mind/body split, consider a human person as having two different natures, e.g., an immaterial mind (or soul), and a physical body. But they have not been able to explain interaction between these two different natures. Most “rationalists” define a person in terms of mind (or soul) only; most “empiricists,” in terms of body only.

All these consider a person only in terms of exercising “functions,” rather than in terms of his/her nature. The rationalist says a person does not begin until he/she can exercise “rational attributes” (self-consciousness, choosing, willing, relating to surroundings, etc.). Empiricists say a person does not begin until he/she can exercise “sentience” (feel pain or pleasure). Virtually none of these bioethics positions match the scientific facts, and are on the verge of the ridiculous. There is no scientific correlation between any physical development of the brain in the womb or later, and the psychological states claimed to relate to that development. In fact, science indicates that neither “rational attributes” nor “sentience” can be fully exercised until early adulthood, when the brain is fully developed!

If philosophy must be invoked at all, then a philosophy which at least matches the correct scientific facts is imperative. For example, in philosophical realism, a human person is defined as one living composite of body and soul together – that is the human nature present. Thus a “person”, differing from the other definitions, would include the mentally ill, the frail elderly, the comatose, paraplegics such as Christopher Reeves, and human infants in the moment of “partial birth,” or human zygotes produced by cloning or by fertilization. Scientifically, there is no point from fertilization (or cloning) to death when the human nature of that human being changes at all; it keeps on continuously creating specifically human enzymes, proteins, tissues and organs – which only a human being can do. Adherence to science will preclude denial of humanhood and personhood to this marvelous creature.

Public policy should reflect accurate science – not myths or biased verbal gymnastics; otherwise they can literally kill. Scientifically, the immediate products of human cloning and fertilization are the same – an already existing, living, unique, individual, embryonic human being. It is not a “pre-embryo”, or a new drug which might fall under the aegis of the FDA. Cloning is harmful destructive human embryo research – research which is already banned in the use of federal funds.

Research that is truly ethical can not be justified simply by having laudable goals (like curing diseases, etc.). The means used toward those goals must be good as well. Since the immediate product of human cloning is a human being, cloning uses that human being as a mere means to someone else’s goals. Therefore human cloning is unethical, and should be banned both publicly and privately.

With better insight into cloning, the “ban” on human embryo research should be revisited, since even federally funded human embryo research is presently going on, e.g., in stem cell research, funded by NIH, which obtains stem cells by exploding (and therefore killing) innocent developing human embryos. State and federal regulations should be extended to ban any human embryo research. Public and private authorities should pursue similar proscriptions within their scope of jurisdiction.

In a strange way we may thank “Dolly” for bringing more light upon practices which for some time have been growing with alarming speed, yet with almost no public – or legislative – attention.


The author is very grateful for important and significant editorial suggestions by Mr. Curran Tiffany, who helped me considerably in translating scientific jargon into readable English.