The emerging consensus among scientists and ethicists is that to keep the human germline safe, gene editing must not be conducted on human embryos that are meant to be used for reproduction, because genetic changes made to embryos may be inherited by the resulting children’s own descendants. This is what is meant by “germline modification” — the modification of the germ cells that transmit genetic information from one generation to the next.
[Other perspectives: CRISPR will change lives, but not only through genetic engineering]
Modifying the genes of embryos that are then destroyed is not germline modification, because the genetic changes are not inherited by future generations. Therefore, destroying embryos that have had their genes modified is thought of as a socially and morally responsible way to conduct research.
The moral status of the embryo is by now a decades-old question in U.S. politics, one that has been closely tied to debates over abortion. But the position that scientists have a moral obligation to kill genetically modified human embryos goes beyond the justifications offered by proponents of abortion for killing unborn human beings. Some proponents of human embryo research have argued that the early embryo, unlike a newborn baby or unborn fetus, is not yet a human being — but they offer no plausible alternative to the moment of conception for when a human life begins.
In the stem cell debates, killing human embryos was seen as a necessary step in generating embryonic stem cells; in the debates over abortion and some forms of contraception, the killing of human embryos was seen as necessary for women to exercise control over their own bodies. Stem cell researchers aim not to kill embryos, but to produce embryonic stem cells for potential medical treatments; women using contraception aim not to kill embryos, but to avoid pregnancy. In the case of killing genetically modified human embryos, however, scientists insist that these embryos must be destroyed as a matter of moral principle.
The mandated destruction of genetically modified human embryos complicates the lessons we can draw from the moral disaster of eugenics. In the early 20th century, the eugenics movement meant to “perfect” the human species through “better breeding,” giving rise to the somewhat ridiculous spectacle of “fitter family” contests, and later, to harebrained schemes for collecting sperm from Nobel Prize winners.
The eugenics movement was also animated by a terror that the gene pool was degenerating. This motivated some of the most shameful public policies in the history of modern democracy, particularly the compulsory sterilization of those deemed to be threats to future generations. Scientists and lawmakers were so concerned with protecting the human species from the specious threat of genetic degeneration that they were willing to trample the rights and interests of actual human beings.
Opponents of human germline modification often point out its similarities with the eugenics movement, in particular the dubious notion that gene-editing techniques can be used to perfect the human race by giving us control over our own evolution. In fact, many scientists and ethicists believe that it is necessary to destroy any genetically modified human embryo because of the eugenic implications of germline modification.
But the idea that we must kill human embryos to preserve the integrity of the human germline bears a troubling similarity to the moral reasoning of the advocates of eugenic sterilization, who believed that killing individuals was worthwhile if it protected the human species as a whole. These scientists elevated abstractions such as the human gene pool above their obligations to individual human beings and families.
A serious response to the moral challenges posed by gene editing would make scientists and doctors responsible not for abstractions, but to actual human beings — and especially to the patients of experimental gene-editing procedures, whether those patients be adults, children or unborn embryos.
Gene editing in embryos is a dangerous form of experimental medicine, and because the research subjects — the embryos — cannot consent to the risks involved, it may never be possible to do this research ethically. But thinking that killing the subjects of preclinical research makes gene editing in embryos morally acceptable is a perverse inversion of the standards of research ethics, and of the obligations we have toward the most vulnerable.
Explore these other perspectives: