Human Cloning

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Human cloning, which occurs naturally but rarely with the birth of identical twins, became a technological possibility with the development of the technique of somatic cell nuclear transfer (SCNT) to clone the first mammal in 1996. As a result of this scientific advance, the prospect of human cloning quickly became a hotly debated ethical issue. As the debate developed it also became common to distinguish reproductive cloning from therapeutic cloning, each being subject to slightly different ethical assessments.

History and Science

Cloning (from the Greek word klon, a twig or slip) is a natural process of asexual reproduction found in many plants and some animals. When strawberry plants send out runners that set roots and turn into new plants, this is an example of a plant naturally cloning itself. Even artificial cloning is not entirely new. For hundreds of years gardeners have taken slips (small shoots or twigs cut from plants) and rooted them to produce new plants in a process that could also be described as cloning. Then in the 1970s scientists began experiments in artificial cloning with frogs and toads, and subsequently with other animal embryos. But it was not until the successful SCNT cloning of the sheep "Dolly," performed in 1996 and formally announced in February 1997 by the Roslin Institute in Scotland, that it became clear something similar might be possible with mammals.

Mammals have two kinds of cells: somatic cells (many of which can reproduce themselves by clonelike division, but only themselves and not a whole organism) and sex cells (which come in two forms, ovum in females and sperm in males). The SCNT process works as follows: The nucleus is removed from a somatic cell of either a female or a male. An unfertilized ovum is taken from a female and has its nucleus removed and then replaced with the somatic cell nucleus. The resulting ovum with a somatic cell nucleus is then stimulated and implanted in a female womb to grow to term. The resulting offspring is genetically identical to the individual that was the source of the original somatic nucleus.

The technology of cloning is thought to be feasible in many mammalian species, including humans. As of 2005, successes in cloning of many species have been achieved. But neither the cloning of primates nor of humans has been successful as yet. Human somatic cell nuclear transfer, if successful in producing offspring, would not be "duplication" because identical genomes do not produce identical phenotypes. Nevertheless, Korean scientists have used cloning technology to produce cloned embryos, and subsequent experiments have furthered such technologies, which are aimed at producing embryonic stem cells for research and therapeutic purposes.

The science and technologies of cloning remain in their infancy. Pharmaceutical companies have not expressed great interest in trying to work to clone people because they see much bigger markets in the cloning of animals and cells. Efforts to create a human clone have been limited largely to groups outside the mainstream of science and medicine, and no one knows for sure whether stem cells derived from cloned human embryos really will prove useful as a way to cure diabetes, liver failure, Parkinson's disease, spinal cord injuries, or any other disease or ailment.

Ethical Concerns

It is easy to see why there is so much interest in and concern about human cloning. There is seemingly no end to the parade of people who issue press releases proclaiming that they are close to success in cloning a human baby. And there is certainly a simple fascination with the technical possibility. Proponents of cloning have also suggested it might serve as a new, unusual, but perhaps efficacious treatment for infertility, enabling those unable to pass genes to future generations to do so in a way that is at least analogous to the familial linkage of twins. And, they point out, scientists have created animal clones and at least a small number of human cloned embryos with hardly any oversight or public accountability.

There are grave risks, however, to any resulting offspring: Mammalian cloning, through the SCNT process, has resulted in the birth of hundreds of organisms. But significantly more nuclear-transfer-generated embryos fail during pregnancy than would fail in sexual reproduction, and a substantial majority of cloned animals who have survived to birth have had some significant birth defect. For these and related reasons President Bill Clinton in 1997 issued a moratorium banning the use of federal funds for human cloning, a position subsequently endorsed by the National Bioethics Advisory Commission.

And for some who believe that any human embryo is a person from the moment of its creation, the fight over human cloning is a fight both about what constitutes membership in the human community and about the morality of abortion. Many opponents of abortion hope that if they can gain legal recognition for cloned human embryos they can then move on to get legal standing for any human embryo or fetus.

One such person is U.S. President George W. Bush. A few months after hearings at the United Nations in

Chronology of Key Early Events in the Human Cloning Discussion
SOURCE: Courtesy of Carl Mitcham and Adam Briggle.
1932Aldous Huxley publishes Brave New World, including the "Bokanovsky Process" for producing cloned children.
1938German embryologist Hans Spemann publishes Embryonic Development and Induction, in which he speculates about the possibility that the nuclei of fully differentiated cells may be able to initiate normal development in enucleated egg cells.
1952U.S. embryologists Robert Briggs and Thomas J. King first successfully transfer nuclei from early embryonic cells of leopard frogs to enucleated leopard frog eggs.
1960s and 1970sBritish developmental biologist John Gurdon makes further advances in cloning frogs. Debates about the implications of cloning begin.
1966U.S. biologist Joshua Lederberg publishes an article in The American Naturalist titled "Experimental Genetics and Human Evolution," in which he speculates on the implications of cloning humans.
1971U.S. geneticist James D. Watson testifies before Congress on the subject of human cloning.
July 25, 1978The birth of Louise Brown, the first baby conceived through in vitro fertilization (IVF), shows that human birth is possible from eggs fertilized outside the body and then implanted in the womb.
1994The National Institutes of Health Human Embryo Research Panel issues a report that deemed research involving nuclear transplantation, without transfer of the resulting cloned embryo to a uterus, as one type of research acceptable for federal support.
1996In the U.S. the Dickey Amendment is enacted, which prohibits federal funding to create human embryos for research purposes and research that destroys or discards human embryos.
July 5, 1996Cloned sheep "Dolly," named after the country singer Dolly Parton, was born using somatic cell nuclear transfer (SCNT).
Feb. 1997Ian Wilmut et al. (Roslin Institute), "Viable Offspring Derived from Fetal and Adult Mammalian Cells," Nature, vol. 385 (27 February), pp. 810–811, announces the birth of Dolly.
March 1997President Bill Clinton issues moratorium banning the use of federal funds for human cloning, and asks the National Bioethics Advisory Commission (NBAC, also sometimes called the National Bioethics Advisory Board) to analyze the ethical issues involved. It issues its report in June 1997.
August 1997Clinton Administration proposes legislation banning human cloning for at least five years, in order to give the NBAC sufficient time for reflection.
Sept. 1997Thousands of U.S. scientists voluntarily commit to a five-year moratorium on human cloning.
Jan. 1998Nineteen European countries ban human cloning.
 Dr. Richard Seed, a Chicago physicist, announces plans to clone a human being.
 U.S. Food and Drug Administration claims authority to regulate human cloning, making it a violation of federal law to attempt cloning without FDA approval.
Nov. 6, 1998University of Wisconsin biologist James Thomson and Johns Hopkins biologist John Gearhart announce the isolation of human embryonic stem cells, sparking increased interest in therapeutic cloning.
Aug. 2000President Bill Clinton announces new guidelines for the federal funding of embryo research, but in early 2001 President George W. Bush places them under review before they are implemented.
Nov. 2000Japan outlaws human reproductive cloning.
July 2001The U.S. House of Representatives passes the Human Cloning Prohibition Act to outlaw both reproductive and therapeutic cloning, but the bill dies in the Senate.
Nov. 2001Scientists at Advanced Cell Technology make unverified reports of the first cloned human embryos.
Dec. 2001Britain outlaws human reproductive cloning.
Feb. 2002United Nations begins consideration of a world-wide ban on human cloning.
July 2002The U.S. President's Council on Bioethics issues its report Human Cloning and Human Dignity: An Ethical Inquiry.
Sep. 2002California becomes the first state to pass a law legalizing therapeutic cloning.
Dec. 2002The Raelians make the unsubstantiated announcement that they successfully cloned a human being.
March 2004Korean scientists announce they have used SCNT to clone human blastospheres.
June 2004United Nations Conference on Human Cloning.

February 2002, Bush announced in a speech from the White House's Rose Garden that he favored a ban on all forms of human cloning, including the cloning of human embryos for the purpose of stem cell research (Bush 2002).

Bush warned that in our zeal to find benefits and cures we could also "travel without an ethical compass into a world we could live to regret." Throughout the rest of his speech were salted words and phrases such as "products," "design," "manufacturing," "engineered to custom specifications." Bush was concerned that cloning would lead to the literal manufacture of human beings. A few months later, on July 10, the President's Council on Bioethics issued a report concluding that moral concerns about human cloning were sufficient to warrant a complete ban on using cloning to make people and a moratorium of at least four years on using cloning for research purposes.

Bush was hardly acting alone in sounding the tocsin of moral concern about the dangers of cloning. He was simply the most prominent among a long list of conservatives, pro-lifers, and neoconservatives, along with a small number of neo-green thinkers, who saw cloning in general as holding the seeds of the degradation of humanity.

Reproductive Cloning

So is there a strong case against human cloning? Reproductive cloning raises the question: Would it be unethical for anyone to try to clone a human being today or at any point in the future? Those who oppose human cloning point to the repugnance of a style of reproduction with such profound potential for vanity, arguing that the freedom of children and the nature of the family are in danger.

There is little debate concerning the claim of most scientists and ethicists that it would be irresponsible and morally wrong to try to use cloning to make a human being anytime soon. The experience of using cloning to make sheep, cows, pigs, and mice has made it abundantly clear that cloning is dangerous. There is real risk of death for the clone and a high risk of disability, and there are also very real risks for the surrogate mother who carries cloned fetuses to term. Without better safety data from animals, including primates, there is no ethical justification for trying to clone a human being.

But safety, while a very real concern, is not a concern about cloning per se. Presume that cloning were to someday prove safe. Would it still be ethically wrong to use it to make people? Any answer that pins the dangers for early prospective clones on something other than mere physical harms novel to the cloning process can become diffused in two conceptual problems:

  • one is attempting to protect future potential persons against harms that might be inflicted by their very existence, and
  • societies around the world have indicated that they believe that the early cloning experiments will breach a natural barrier that is moral in character, taking humans into a realm of self-engineering that vastly exceeds any prior experiments with new reproductive technology.

Laws that would regulate the birth of a clone are philosophically difficult in part because they traverse complex jurisprudential ground: protecting an as-yet-non-existent life against reproductive dangers, in a Western world that, in statutory and case law at least, seems to favor reproductive autonomy.

Many people seem inclined to put those philosophical issues, nonetheless, into a position of primacy in the human cloning debate, including President Bush and his chief bioethical adviser, Leon R. Kass. But the case against cloning when safety is taken out of the equation is a more difficult case to make than that which pivots upon safety alone. This is true whether one considers merely reproductive cloning or cloning for the sake of embryonic-based stem cell therapies.

One such argument against cloning people is that it is wrong to manufacture people. But cloning human beings is no more manufacturing them than using test-tube baby technology or artificial insemination or even neonatal intensive care. No one feels any less human for having been born in a neonatal unit or delivered by forceps or started up in a petri dish. Clones would be no less people with free will and human dignity than any other person.

Or would they? Some contend that cloning is wrong because everyone is entitled to their own unique genetic endowment. This too is not a strong argument because identical twins and triplets already exist and do quite well despite the existence of another person with the exact same genes. Even if one is worried that parents will try to manipulate or force the clone to behave or develop in certain ways, it has to be said that this is precisely what parents do with their children all the time whether they have a genetic tie to them or not. Should laws against cloning reach into social preferences about how children should be raised that are not enshrined in law?

Therapeutic Cloning

Even if the case against human reproduction by means of cloning is not as strong as it may initially appear, there remains the separate issue of human therapeutic cloning. Therapeutic cloning is not intended to create another human being. It employs SCNT to use the results for other purposes. Is it moral to create cloned human embryos simply to destroy them for the purposes of obtaining stem cells to use in medical research or for other potential uses?

Those who oppose the use of cloned embryos for research or therapeutic purposes do so on the basis of two arguments. First, they may oppose therapeutic human cloning weakly, on the grounds that the cloned embryos are potential human life and as such deserve respect. The opposition here is weak only insofar as it need not entail an opposition without compromise. Second, they may oppose therapeutic human cloning more strongly, on the grounds that embryos have the status of human beings from the moment of conception. Here this opposition is more likely to be one that resists any compromise.

In response to the stronger opposition the fact remains that left in a dish in a lab a cloned human embryo has no potential for personhood unless one assumes the voluntarism of highly trained specialists and of women with empty wombs. Even then such embryos are only dubiously embryonic in that their potential to develop in a human uterus has been anything but established, and their differences from "ordinary" embryos—whether or not one considers such embryos to be persons—have been shown to be abundant and significant. So it is not self-evident that it is immoral to make and destroy cloned embryos on the grounds that this is the same as killing a human being.


National debates and those at the United Nations on whether or not to ban human cloning, either outright or merely for reproductive purposes, remain significant venues for science, technology, and ethics interactions. On the one hand, there may be considerable public policy difficulties in implementing any restrictions on reproductive cloning that does not also limit therapeutic cloning, because the initial SCNT technology (or some future technique of a related sort) would be the same for both purposes. On the other hand, it may be that reproductive cloning will remain morally unacceptable simply because it will always be too dangerous or too risky for the future offspring.

At the same time the irony may be that cloned human embryos, which arguably lack true personhood, will remain the best source for stem cells for research and therapeutic uses—uses that may enable humans to respond more effectively to dangers and risks from illness, disease, and injury. Yet because of the potential value of human stem cell research there are also active programs to develop ways to create such cells without involving human embryos. That there might be a technological fix for the moral divide between those in favor and those opposed to stem cell research remains a distinct possibility.

Either way, those who argue about the moral status of human clones and the processes that produce them represent the widest variety of perspectives—in what may almost be called the "kitchen sink" of bioethical debates, involving as they do as many obvious issues about cloning as one could conjecture, as well as a number of subtle issues that depend on careful science and good public policy. On the positive side are proponents such as Michael Fumento (2003) who see human cloning as part of a wave of historically unprecedented benefit and power. On the negative side are critics such as Francis Fukuyama (2002) who see threats to the very nature of humanity. How well society handles human cloning will demonstrate not only how it handles one of its most extreme and extraordinary cases of conflict in medicine, but also how prepared it is for a world in which different kinds of personhood and parenthood may become as ubiquitous as new kinds of food and transportation.


SEE ALSO Embryonic Stem Cells; Eugenics; Playing God; Posthumanism.


Bush, George W. (2002). "President Bush's Remarks in Opposition to Human Cloning" (speech in the Rose Garden, Washington, DC, April 10). In The Future Is Now: America Confronts the New Genetics, ed. William Kristol and Eric Cohen. A brief articulation of the president's view of human cloning.

Fukuyama, Francis. (2002). Our Posthuman Future. New York: Farrar, Straus and Giroux. A defense of the position that cloning is dangerous because it changes human nature.

Fumento, Michael. (2003). Bioevolution: How Biotechnology Is Changing Our World. San Francisco: Encounter Books. An exploration of biotechnology and ethics.

Kass, Leon R., and James Q. Wilson. (1998). The Ethics of Human Cloning. Washington, DC: AEI Press. Leaders in genetics articulate a strategy for regulation of human cloning.

Klotzko, Arlene Judith, ed. (2001). The Cloning Sourcebook. Oxford: Oxford University Press. A compilation of essays concerning the global debate on cloning.

Kristol, William, and Eric Cohen, eds. (2002). The Future Is Now: America Confronts the New Genetics. Lanham, MD: Rowman and Littlefield. A conservative position on human cloning.

McGee, Glenn. (2000). The Perfect Baby, 2nd edition. Lanham, MD: Rowman and Littlefield. A pragmatic position on human cloning.

McGee, Glenn. (2004). Beyond Genetics: A User's Guide to DNA. New York: Harper Perennial. An introduction to cloning and genetic technology.

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Human Cloning

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