THE MERCK VETERINARY MANUAL
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Controversies About Cloning

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Ethical concerns about cloning may be broadly divided into two categories: concern about the effect of cloning on animal and human welfare, and objection to the principle of cloning, ie, to producing an animal by a means other than fertilization.

Currently, cloning is associated with an increase in animal suffering when compared with production of animals by standard breeding methods. This is due to surgeries performed to obtain oocytes or transfer embryos, pregnancy losses, sickness and death of neonates, low-level abnormalities in surviving young, and possible distress from disease in animals produced as disease models. These concerns are somewhat mitigated by the fact that most of these findings are not unique to cloning; they are also associated with other procedures that have been generally accepted as worthwhile, such as in vitro fertilization and embryo production, oocyte transfer, and embryo transfer. In addition, the accepted normal fate of many species being cloned is to be housed for maximal production and then be slaughtered and eaten. A compelling argument for cloning is that the potential benefits of the procedure to the understanding of life processes and animal disease, to human health, and to food production outweigh the cost of the procedure in terms of animal welfare.

Additional concerns rest with the effect of cloning on the entire animal population, most commonly related to the genetic variation of the species. This is a legitimate concern in some species and uses, such as in dairy cattle, in which one bull may sire thousands of offspring. However, this is more related to the technology of semen freezing and distribution than to the fact that a bull itself was cloned. In companion animals, it is improbable that the very few pets likely to be cloned will have an effect on the population in general. In horses, cloning may in fact increase genetic variation, because a major proposed use is to clone geldings that have been found to be superior competitors, thus rescuing genetic types that would otherwise have been lost.

Concerns about human health focus mainly on consumption of food produced from cloned animals. After years of study, the FDA and the European Food Safety Authority have concluded that consumption of meat or milk from cloned animals poses no public health risk. Therefore, remaining concerns about consumption of food from cloned animals is likely based more on principle than on actual potential for harm. Because cloning is used to produce transgenic animals, many perceived concerns regarding cloning are actually concerns about transgenic animals, which present a completely different set of potential hazards to animal and human health and the environment. European nations have relaxed their position on use of cloned animals and their progeny in the food chain based on the lack of evidence of a human health risk and the difficulty in establishing a tracing or labeling system to identify such meat when coming from outside countries.

A key ethical question regarding the principle of producing animals by cloning is whether this technique is violating some moral prohibition; ie, that people are “playing God” by producing embryos without using fertilization. Similar questions have arisen with each new reproductive technique that has been developed; however, many people feel that cloning is a special case. This general moral aversion of the public to the concept of cloning is enhanced by the portrayal of cloning as a malevolent force in science fiction books and films.

Counter-arguments to these moral concerns are that cloning occurs in nature in the form of identical twins; that people have been producing plants and animals by “unnatural” means from the first time they planted a seed in a new area or bred a cow to a selected bull, and that this is simply a new development in the same line. Embryonic cloning was being performed for more than 10 years before the birth of Dolly with essentially no public attention, and even the birth of two lambs cloned from cultured cells of embryonic origin, announced a year before Dolly, had no public impact. Thus, it appears that the main moral issue of public concern is not the production of embryos without fertilization, but the production of embryos from cells of an existing, known animal.

Arguments against cloning of companion animals have focused on the cost of producing a clone—tens to hundreds of thousands of dollars—when millions of unwanted dogs and cats are killed each year. However, people currently buy purebred dogs and cats for thousands of dollars when they could get animals for free. American culture supports the concept that people can spend their own money on whatever they wish.

A related argument is that cloning turns animals into a commodity or an object, rather than a sentient being, and that producing an animal in this way shows a lack of respect for the animal as an individual. However, animals have been bought and sold since they were domesticated; currently semen and embryos are frozen, shipped across the country, and used to produce desired young. Cloning does not seem to offer any unique distinction in this area.

Commercialization of cloning brings with it the possibility of fraud and of preying on the emotions of bereaved pet owners. Cloning companies should state clearly that the technique will produce another individual with the same genetics as the original animal; it does not “resurrect” an animal. The best simile to draw is to that of an identical twin born later in time; just as with naturally occurring identical twins, they will be very similar but also different in many ways.

Last full review/revision November 2013 by Katrin Hinrichs, DVM, PhD, DACT

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