Because genetic diagnosis of embryos involves genetically-based selection of embryos, its eugenic potential cannot be denied. It is not the technique in itself, however, that represents a eugenic threat, but rather the potential for social uses to be made of it. Although consensus is lacking on the definition of eugenics, the general agreement is that the term refers to practices aimed at improving the hereditary traits of the human species through deliberate intervention. Viewed from this angle, preimplantation genetic diagnosis is too marginal a practice to be considered eugenic.
The World Health Organization defines eugenics as “[a] coercive policy intended to further a reproductive goal, against the rights, freedoms, and choices of the individual,”6
thereby emphasizing the importance of protecting individuals from a collective force. To avoid rhetorical distortion and to better understand the ethical issues associated with practices that link genetics and reproduction, it is wiser not to place all such practices under the heading of eugenics without nuance. For example, offering the selection of embryos for the avoidance of rare disorders may be considered by some to be discriminatory or immoral. But as long as this practice is not imposed, it is only potentially
eugenic. This argument is all the more pertinent given that the technical limitations inherent in preimplantation genetic diagnosis do not even allow for its use in the service of any eugenic policy.7
Moreover, genetic diagnosis of embryos requires prior in vitro fertilization and all the procedure entails;8
it is expensive and it does not allow for a large number of children per family.9
In short, this technique is too complex and humanly too exacting to be seriously considered “eugenic.” A society that would wish to rid itself of all embryos that did not satisfy certain criteria would resort to prenatal diagnosis, not genetic diagnosis of embryos, since diagnosing fetuses is more feasible, less expensive and more cost effective. Finally, most countries have placed legal and ethical limitations on preimplantation genetic diagnosis (Appendix 4, available at www.cmaj.ca/cgi/content/full/cmaj.080658/DC1
For example, some countries, including Austria, Germany and Switzerland, legally prohibit the technique. Others, including the United Kingdom, France and the Netherlands, permit it with certain exceptions. In Canada, preimplantation genetic diagnosis is permissible under the legislative framework of the law on assisted human reproduction. The United States has no legal regulations but allows the technique to be regulated by professional standards.