Germline Modification Carries Risk of Major Social Harm

Your Editorial 'New sources of sex cells' (Nature 452, 913; 2008), on the potential use of pluripotent stem-cell-derived gametes (PSCDGs) for germline genetic modification and enhancement, suggests that the prospect of stem-cell-derived gametes could trigger renewed calls for regulating human biotechnologies. In those discussions we must, as you warn, be wary of impeding basic research. But we must be equally willing to draw lines proscribing socially pernicious applications.

Germline (that is, inheritable) modification is the most socially consequential and ethically dubious application of human biotechnology; its implications have been explored from a wide range of perspectives. Most of these discussions have focused on the social meaning and repercussions of genetic manipulation of the human species, not on the moral status of human embryos. One can strongly support human-embryo research and still oppose germline modification. Conversely, some opponents of abortion rights support germline modification, so long as no embryos are destroyed in the process.

Although there may be scientific and therapeutic benefits from research on PSCDGs, the case for any such benefits from using these cells for human germline modification is...