Cloning
Cloning
Cloning
First published Wed Sep 17, 2008 Dolly, the first mammal cloned from an adult body cell, came into the world as innocent as a lamb; but she has caused panic and controversy, as well as a vast academic and popular literature on the ethics and regulation of cloning. Following the announcement of her birth in February 1997 (Wilmut et al. 1997), an important question arose: if the cloning of mammals is possible, will scientists soon start cloning human beings as well; and if they did, would this be wrong or unwise? More than ten years later, many countries have legally prohibited human cloning or are in the process of doing so, and various institutions, including the United Nations and the European Parliament, are calling for a worldwide ban on all forms of human cloning. This entry describes the most important areas of disagreement regarding the ethics of human cloning, since human cloning has been the main topic of the cloning debate.
1. What is Cloning?
Strictly speaking, cloning is the creation of a genetic copy of a sequence of DNA or of the entire genome of an organism. In the latter sense, cloning occurs naturally in the birth of identical twins and other multiples. In the debate over cloning, however, the termcloning typically refers to somatic cell nuclear transfer (SCNT). SCNT involves transferring the nucleus of a somatic cell (any body cell other than a sperm or egg cell) into an enucleated oocyte, i.e. an oocyte from which the nucleus and thus most of the DNA has been removed. The manipulated oocyte is thereupon treated with chemicals or electric current in order to stimulate cell division and an embryo is formed. Because the embryo's nuclear DNA is that of the somatic cell it is genetically identical to the organism from which the somatic cell was obtained. Dolly the sheep was the first mammal ever to be cloned using SCNT. Ian Wilmut and his team at the Roslin Institute in Scotland replaced the nucleus from an oocyte taken from a Blackface ewe with the nucleus of a cell from the mammary gland of a six-year old Finn Dorset sheep. They transferred the resulting embryo into the womb of a surrogate ewe and approximately five months later Dolly was born. Dolly had a white face. She was genetically identical to the Finn Dorset ewe from which the somatic cell had been obtained. Dolly, however, was not 100% genetically identical to the donor animal. Genetic material comes from two sources: the nucleus and the mitochondria in the cytoplasm of a cell. Mitochondria are organelles that serve as power sources to the cell. They contain short segments of DNA. In Dolly's case, her nuclear DNA was the same as the donor animal; other of her genetic materials came from the mitochondria in the cytoplasm of the enucleated oocyte. For the clone and the donor animal to be exact genetic copies, the oocyte too would have to come from the donor animal (or from the same maternal line as mitochondria are passed on by oocytes).
Dolly's birth was a real breakthrough, for it proved that something that had been considered biologically impossible could indeed be done. Before Dolly, scientists thought that cell differentiation was irreversible: they believed that, once a cell has differentiated into a specialized body cell, such as a skin or liver cell, the process cannot be reversed. What Dolly demonstrated was that it is possible to take a differentiated cell, turn back its clock, and make the cell behave as though it was a recently fertilized egg. Nuclear transfer can also be done using a donor cell from an embryo instead of from an organism after birth. Cloning mammals using embryonic cells has been successful since the mid-1980s (for a history of cloning, see Wilmut et al. 2001). Another technique to produce genetically identical offspring or clones is embryo twinning or embryo splitting, in which an early embryo is split in vitro so that both parts, when implanted in a womb, can develop into individual organisms genetically identical to each other. This process occurs naturally with identical twins. The cloning debate, however, has focussed on the use of SCNT. There are two possible uses of SCNT: creating cloned human embryos to use in research and therapy, and creating human embryos with the intention of gestating them into full-grown human beings. The latter is calledreproductive cloning. The former is often referred to astherapeutic cloning, but in this entry it will be discussed under the heading cloning for research and therapy. Both reproductive cloning and cloning for research and therapy involve SCNT, but their aims, as well as most of the ethical concerns they raise, differ. We will first discuss cloning for research and therapy and will then proceed to outline the ethical debate surrounding reproductive cloning.
derivation of human embryos by SCNT is still in its infancy stages, and no research team has succeeded in deriving hES cells from human clones. Cloning for therapy is thus not likely to bear fruition in the short term, if it will ever prove valuable at all. Apart from unsolved technical difficulties with nuclear transfer, much basic research in embryonic stem cell research would be needed. The term therapeutic cloning has been criticized precisely for this reason. It suggests that therapy using embryonic stem cells from cloned embryos is already reality. In the phase before clinical trials, critics say, it is only reasonable to refer to research on nuclear transfer asresearch cloning or cloning for biomedical research (President's Council on Bioethics (PCBE) 2002, de Wert and Mummery 2003). Cloning for research will in all likelihood be the most promising application of SCNT. Researchers could create large numbers of stem cells genetically identical to the patient and then experiment on these in order to understand the particular features of the disease in that person. The increased possibility to study disease in a dish would enable research that cannot be done in patients themselves or where there are too few patients to work with as in the case of rare genetic diseases. Stem cells genetically identical to a patient would also be of great value for drug screening and toxicity testing. For example, hepatocytes (liver cells) derived from stem cells that were obtained from embryos genetically identical to patients with various genetic and disease backgrounds could be used for predicting the liver toxicity of candidate drug therapies. Cloning for research and therapy seems to show great promise for future research and perhaps therapy, then; but it has also raised various concerns.
for these purposes is not. According to this view, the morally relevant difference is that, in the case of surplus IVF embryos, each of the embryos was created in the hope that it would develop into a child. Each embryo was created for its own sake, or at least had a chance to continue living. By contrast, in cloning for research, embryos are created for instrumental use only; they are created and treated as a mere means, which some regard as incompatible with a respectful attitude towards the embryo (National Bioethics Advisory Commission (NBAC) 1999). Others (including both proponents and opponents of the use of embryos in research) have denied that there is a moral difference between using surplus IVF embryos and cloned embryos as a source of stem cells. In their opinion, if killing embryos for research is wrong, it is wrong regardless of the embryo's origin (Doerflinger 1999, Devolder 2005). A less common view states that obtaining stem cells from cloned embryos poses fewer ethical problems than obtaining stem cells from surplus IVF embryos. Hansen (2002) has advanced this view, arguing that embryos resulting from SCNT do not have the same moral status we normally accord to other embryos: he calls the combination of a somatic nucleus and an enucleated egg a transnuclear egg, which, he says, is a mere artifact with nonatural purpose or potential to evolve into an embryo and eventually a human being, and therefore falls outside the category of human beings. McHugh (2004) and Kiessling (2001) advance a similar argument. On their view, obtaining stem cells from cloned embryos is less ethically problematic because embryos resulting from SCNT are better thought of as tissue culture, whereas IVF represents instrumental support for human reproduction. Since creating offspring is not the goal, they argue, it is misleading to use the term embryo or zygote to refer to the product of SCNT. Their suggested terms includeclonote and ovasome.
outcome for the patient, is violated in the case of egg donation for cloning research (George 2007). Mertes and Pennings (2007) believe that although it makes sense to regard non-medical oocyte donors as a special category, that doesn't mean that there are new ethical issues to be considered. Their view is that oocyte donation for cloning should be approached with the same set of principles that are currently applied to other types of research with healthy research subjects: risks and benefits need to be balanced, and concerns about informed consent and possible undue inducement or exploitation of research donors should be carefully considered. Given the risks for the donor in the absence of direct medical benefit, and given that the benefits for research are uncertain, it is not surprising that the number of altruistic non-medical oocyte donations is very low. Financial incentives might be needed to increase the supply of oocytes for cloning research. But this raises concerns about the commodification of human reproductive material, undue inducement, and the exploitation of women. In some countries, including the US, selling and buying eggs is legal. Some object to these practices because they consider oocytes as integral to the body and think they should be kept out of the market: on their view, the value of the human body and its parts should not be expressed in terms of money or other fungible goods. Some also worry that, through commercialization of oocytes, women themselves may become objects of instrumental use (Alpers and Lo 1995). Many agree, however, that a concern for commodification does not justify a complete ban on payment of oocyte donors and that justice requires that they be financially compensated for the inconvenience, burden, and medical risk they have endured, as is standard for other research subjects (Steinbock 2004, Mertes and Pennings 2007). A related concern is the effect of financial or other offers of compensation on the voluntariness of oocyte provision. Women, especially economically disadvantaged women from developing countries, might be unduly induced or even coerced into selling their eggs (Dickinson 2002). Baylis and McLeod (2007) have highlighted how difficult it is concomitantly to avoid both undue inducement and exploitation: a price that is too low risks exploitation; a price that avoids exploitation risks undue inducement. Concerns about exploitation are not limited to concerns about payment, as became clear in the Hwang scandal (for a review, see Saunders and Savulescu 2008). Woo-Suk-Hwang, a leading Korean stem cell scientist, had claimed to be the first to clone human embryos using SCNT and to extract stem cells from them. In addition to find that Hwang apparently fabricated many of his research results, Korea's National Bioethics Committee also found that Hwang had pressured junior members of his lab to donate eggs for his cloning experiments. Some authors have argued that regulating the market in oocytes could minimize ethical concerns raised by the commercialization of oocytes and could be consistent with respect for women (Resnik 2001, Gruen 2007). Researchers are also investigating the use of alternative sources of oocytes for cloning research, including fetal oocytes, and eggs from adult ovaries obtained post mortem or during operation, oocytes derived from stem cells, as well as animal oocytes. Others have suggested asking people about to undergo IVF to donate one or two of their oocytes, perhaps in return for a reduced fee for their fertility treatment, as these women already face the risk of hormone stimulation. If cloning for therapy becomes an option, families, eager to help
their dying or sick relative, may well volunteer sufficient oocytes for the treatment of their sick relative.
This promise notwithstanding, many scientists have warned that it would be premature to stop all cloning research. iPS cells are not identical to embryonic stem cells and different methods of obtaining pluripotent stem cells might prove more useful for particular purposes. Cloning, for example, may be capable of teaching us things that iPS cells cannot, and different diseases might be treatable by different types of stem cells or some combination of stem cells.
child with a wide array of possible life plans. Another possible use of reproductive cloning is to help create a child that is a tissue match for a sick sibling. The stem cells from the umbilical cord blood or from the bone marrow of the cloned child could be used to cure the diseased child. Such children, referred to assaviour siblings, have already been created through sexual reproduction or, more efficiently, through a combination of IVF, preimplantation genetic diagnosis and HLA testing. Many people, however, have expressed objections to human reproductive cloning and think it should be legally prohibited worldwide. Some have no objections to reproductive cloning but do not promote it either. In criticising the arguments that have been produced against cloning they sometimes have been misidentified asdefenders of cloning. However, they seldom recommend the practice, being for the most part content to expose the problematic nature of many of the arguments against it. What follows is an outline of some of the main areas of concern and disagreement about human reproductive cloning.
then, is whether, if cloning does become safe and efficient, those who condemn cloning because of its experimental nature should continue to condemn it morally and legally. Some authors have reasoned that if, in the future, cloning becomes safer than sexual reproduction, perhaps they should instead make it our reproductive method of choice (Fletcher 1988, Harris 2004 chapter 4).
consequently, may violate a right to ignorance about one's future (Jonas 1974) or to an open future (Feinberg 1980). Even if it is not only genes that determine who and what we become, the cloned individual's perception may still limit a sense of self and independence and thus reduce his or her autonomy, these commentators argue. Others disagree (Harris 1997 and 2004, Tooley 1998, 845, Brock 1998, Pence 1998). They believe the aforementioned concerns involve a misguided belief in genetic determinism that could be minimized by adequate education and information. Further, they argue, even if people persist in these mistaken beliefs and their attitudes or actions lead to cloned individuals believing they do not have an open future, this does not imply that the clone's right to ignorance about one's personal future or to an open future has actually been violated (Brock 1998, Buchanan et al. 2000, 198). Some authors have also pointed out that a younger twin could derive benefits from knowing the older twin's life-course, as he or she can learn from the older twins' mistakes (Brock 1998, 154). Others point to comparisons with what we already accept in sexual reproduction. Harris (2004, chapter three), for instance, has argued that if possible psychological harm arising from knowledge of one's genetic origins is a sufficient ground to ban reproduction, then interference in reproductive liberty would be very frequent, as there are many children now who experience psychological harm because of such knowledge. Pence and others point out that high expectations are true of most parenting and that parents with high expectations nonetheless usually give their children the best chances to lead a happy and successful life (Pence 1998, 138). Many of these critics also argue that parents reduce or increase the array of life plans available to their children all the time through non-genetic means such as their education. In their view, rather than prohibiting cloning, the more rational strategy would be to concentrate on how we can help to prevent parents from restricting the array of available life plans open to their children, regardless of the way in which the children were conceived. 3.2.2 Replacement Children In 2004, US fertility doctor Panos Zavos claimed to have created a cloned embryo using tissues from deceased people, one of them an 11-year-old girl who had died in a car crash. Such a result, he stated, pointed to the possibility that people in the future could replace the deceased. Cloning for the purpose of trying to create a replacement child has raised the concern that parents will compare the new child with the deceased child and that the ghost of the dead child will get more attention and devotion than its replacement, which could adversely affect the replacement child's self-esteem. Parents may expect the child to be like the lost child, or some idealized image of it, which could hamper the development of the replacement child's own identity (Levick 2004, 11132). Many people agree that, should reproductive cloning ever become a new reproductive technique, efforts should be made to help candidate parents understand that bringing loved ones back to life is impossible and that the child created through cloning is a different person. Others are less concerned with this issue, arguing that, even if their intentions or reasons are misguided, creating a replacement child is one of the many self-centered reasons why people decide to have children and is not intrinsically related to cloning (Brock 1998, 1489; Pence 1998, 13140). 3.2.3 Awareness of Genetic Predispositions for Diseases
Another area of disagreement is the impact on the individual conceived through cloning of his or her knowledge about the genetically identical predecessor's medical history. For instance, a person conceived through cloning who knows that his genetic parent has developed a severe single gene disease at the age of forty knows chances are very high that the same will happen to him or her. Unlike people who choose to have themselves genetically tested, clones who know their genetic parent's medical history will be involuntarily informed. Disagreement exists on whether or not this is a good thing. Some have pointed out that having information about one's genetic predispositions can prolong one's life by suggesting methods of reducing the risks revealed by genetic information, including behavioural changes and preventive medication. Others are concerned about psychological consequences for the clone, especially when the inherited disease is non-treatable, as is the case with Huntington's disease. Concerns about genetics leads others to the opposite conclusion: John Harris, for instance (2004, chapter 1), argues that when we clone we can have available a tried and tested genome, not one created by the genetic lottery of sexual reproduction and the random combination of chromosomes. If we choose our cell donor wisely, Harris argues, we will be able to protect the clone from many hereditary disorders and many other genetic problems. 3.2.4 Societal Prejudice and Respect for Clones Some are concerned that clones may be the victims of discrimination who will not be respected as full persons (Deech 1999, Levick 2004, 185, 187). Savulescu (see 2005 in Other Internet Resource) has referred to possible negative attitudes towards clones asclonism: a new form of discrimination against a group of humans who are different in a non-morally significant way. Savulescu and others have argued that concerns about such discriminatory reactions and prejudicial attitudes is not a sound ground for banning cloning; they argue that, rather than limiting people to make use of assisted reproduction techniques, we should combat existing prejudices and discrimination (see also Pence 1998, 46, Harris 2004, 923). Macintosh (2005, 11921) has warned that these prejudices as well as misguided stereotypes about human clones are actually reinforced by common objections to cloning. For example, saying that a clone would not have a personal identity prejudges the clone as inferior or fraudulent (the idea that originals are more valuable than their copies) or even less than human (as individuality is seen as an essential characteristic of human nature). 3.2.5 Complex Family Relationships Another concern is that a cloned individual would be confused about his or her kinship ties (Kass 1998, O'Neil 2002, 678). Cloning, it is worried, will blur generational boundaries. For example, a woman who has a child conceived through cloning would actually be the twin of her child and the woman's mother would, genetically, be its mother, not grandmother. Some have argued against these concerns, replying that a cloned child would not necessarily be more confused about his or her family ties than other children. There are children now who never knew their genetic parents, or whose nurturing parents are not their genetic parents, or who think that their nurturing father is also their genetic father when they were actually conceived with the sperm of the nurturing mother's lover, or have four nurturing parents because of a divorce, or are nurtured by their grandparents. While these complex family relationships can be troubling for some
children, they are not insurmountable, these critics say. As with all children, the most important thing is the relation with people who nurture and educate them, and children usually know very well who these are (Harris 2004, 778). Onora O'Neil (2002, 678) argues that such responses are misplaced. While she acknowledges that there are already children now with confused family relationships, she argues that it is very different when prospective parents seek such potentially confused relationships for their children from the start.
One of the major concerns raised by cloning is that it could lead to eugenic practices. In one sense of the term, eugenics is a positive notion: as Buchanan et al. (2000, 56) have pointed out, the core notion of eugenics, that people's lives will probably go better if they have genes conducive to health and other advantageous traits, has lost little of its appeal. And some see the increase in control of what kind of genome we want to pass to our children as a positive development (Fletcher 1988, Harris 1997 and 2004, Pence 1998, 1016, Tooley 1998). But this shift from chance to choice also raises several issues (for an extensive analysis, see Buchanan et al. 2000). First, the history of eugenics includes some of the darkest chapters of the western world in the 19th and 20th centuries (for a history of eugenics as well as an analysis of philosophical and political issues raised by eugenics, see Kevles 1985 and Paul 1995). The eugenic movements in the 19th century in the United States and Europe were responsible for hundreds of thousands of forced sterilizations, and the Nazi eugenic programs during World War II involved some of the cruellest crimes against humanity, all in the pursuit of so calledracial hygiene. More recently, the language of eugenics has made a comeback, not only among critics but also amongst proponents of these new biotechnologies. Some have called for a new liberaleugenics (Agar 2004). Unlike the coercive and state-directed eugenics of the past, liberal eugenics defends values such as autonomy, reproductive freedom, beneficence, empathy and the avoidance of harm. Enthusiasts of liberal eugenics are interested in helping individuals to prevent or diminish the suffering and increase the well-being of their children by endowing them with certain genes. However, disagreement exists about whether and to what extent the new liberal eugenics really differs from eugenic programs in the past (Buchanan et al. 2000, Habermas 2003, Sandel 2007, 7583). According to Sandel (2007, chapter 5), for instance, liberal eugenics might imply more state compulsion than first appears: just as governments can force children to go to school, they could require people to use genetics to have better children. Because cloning can be used to create better people by copying the genome of people with desirable characteristics, some are concerned that it may set a precedent for more problematic non-therapeutic interventions, such as height, eye color and intelligence This entry is not the right place to give an account of all the concerns raised by enhancement technologies, but two important issues are directly related to cloning. Sandel (2007, 527) has argued that cloning and enhancement technologies may result in a society in which parents will not accept their child for what it is, reinforcing an already existing trend of heavily managed, high-pressure child-rearing or hyper-parenting. Asch and Wasserman (2005, 202) have expressed a similar concern; arguing that having more control over what features a child has can pose an affront to an ideal of unconditioned devotion. The second concern, most often expressed by disability rights advocates, is that if cloning is used to have better children, it may create a more intolerant climate towards the disabled and the diseased, and that such practices can express negative judgments about people with disabilities. This argument has also been advanced in the debate about selective abortion, prenatal testing, and preimplantation genetic diagnosis. Disagreement exists about whether these effects are likely. For example, Buchanan et al. (2002, 278) have argued that one can devalue disability while valuing existing disabled people and that trying to help parents who want to avoid having a disabled child does not imply that society should make no efforts to increase accessibility for existing people with disabilities.
be raised in no less loving way than is normally the case (Harris 2004, 41 2, Pence 1998, Devolder 2005). McDougall (2008) and Birmbacher (2008) have argued not that cloning is in itself a violation of human dignity, but that it can be under certain circumstances, as, for example, when it would divert scarce resources away from those who lack sufficient health to enable them to exercise basic rights and liberties.
4. Religious perspectives
No unified religious perspective on human cloning exists; indeed, there are a diversity of opinions within each individual religious tradition. For an overview of the evaluation of cloning by the main religious groups see, for example, Cole-Turner (1997) and Walters (2004). For a specifically Jewish perspective on cloning, see, for example, Lipschutz (1999), for an Islamic perspective, Sadeghi (2007) and for a Catholic perspective, Doerflinger (1999).
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