Next month, the US Food and Drug Administration will hold a two-day public meeting to discuss genetic modification within the human egg, which changes will be passed on generationally.

Human gene therapy has been ongoing since 1990, but most of that involved non-heritable genes, called somatic (non-sex cell) gene therapy. Somatic modifications only affect the individual and are not passed on, and so do not affect the human genome.

The game changed with the successful birth of at least 30 genetically modified babies by 2001. Half of the babies engineered from one clinic developed defects and so the FDA stepped in and asserted jurisdiction over “the use of human cells that receive genetic material by means other than the union of gamete nuclei” (sperm and egg).

Now the FDA is considering going forward with “oocyte modification” which involves genetic material from a second woman, whereby offspring will carry the DNA from three parents. These kinds of genetic changes (“germline modification”) alter the human genome.

This is the first such meeting ever to be held in public by the FDA, reports...