Of course, once genetic germline engineering becomes technically feasible, researchers would want to conduct studies in animals to make sure practices were safe before trying them in people. Obstacles now to germline engineering are practical, not theoretical. Because every cell in the body is a descendant of that first fertilized egg, every cell would have a copy of the artificial chromosome. Artificial chromosomes, even human artificial chromosomes, have been created and patented, the scientists reported, and companies have sprung up to exploit the technology. No problem, said Dr. Mario R. Capecchi, a distinguished professor of biology and human genetics at the University of Utah.
Biologists already know how to make artificial chromosomes that can self destruct on command.
The lone ethicist speaking at the conference was Dr. John Fletcher, who was chief of bioethics at the National Institutes of Health and is now a professor of biomedical ethics at the University of Virginia. He said he had no problems in principle with giving people genes that would prevent or cure diseases. But, he said, he is troubled by the idea of adding genes for certain complex traits. He said he finds this kind of talk problematic. However, he added, there is nothing intrinsically unethical about germline genetic engineering.