A pressing question, said Rudolf Jaenisch, an M.I.T. biology professor, is why anyone would want to edit the genes of human embryos in order to prevent disease. Even in the most severe cases, involving diseases like Huntington’s in which a single copy of a mutated gene inherited from either parent is enough to cause the disease with 100 percent certainty, editing poses ethical problems. Because of the way genes are distributed in embryos, when one parent has the gene, only half of the parent’s embryos will inherit it. With gene editing, the cutting and pasting has to start immediately, in a fertilized egg, before it is possible to know if an embryo has the Huntington’s gene. That means half the embryos that were edited would have been normal — their DNA would have been forever altered for no reason. “It is unacceptable to mutate normal embryos,” Dr. Jaenisch said. “For me, that means there is no application.”
If I were grading an undergraduate philosophy class, I am not sure Dr. Jaenisch would exceed a C minus with that answer (the source article is here). Besides I have never known a normal embryo. Then there is the all too obvious question as to why it should be acceptable to abort embryos, but not to modify or mutate them. Oops.
The better arguments are surely the slippery slope worries that embryo tinkering will change the nature and future of humanity in dangerous ways, perhaps producing too much conformity, too much zero-sum competition (“buy the Harvard splice”), too much discrimination against various “types,” too much induced family loyalty, legal discouragement of rebellious genes, excess advantages for elites, too many decisions which too explicitly lower the social status of some groups of people, and perhaps ultimately too much drift from the world we know (and love?).
Those are my worries. Whether or not they are valid, they would seem to merit at least a C+. But many commentators wish to ensure these issues are not actually argued. Will this prove the new face of anti-scientific, anti-philosophical thinking? Check out the closing quotation from Professor Daley at Harvard, and his use of the word “deranged.”
A lot of parents will strongly desire some future version of this product, and I believe a number of countries are going to be willing to proceed with such innovations, if and when they become possible. They’ll also be willing to live with the costs of the failures in the meantime. So I don’t think the strategy of shutting down debate is going to fare so well in this case.