leon R. Kass, the University of Chicago ethicist who was the brains behind the Bush administration’s bioethics policy, has resigned as the chairman of the President’s Council on Bioethics. He will remain as a member of the Council. A spokeswoman said that Dr Kass “loved the job” but had felt increasingly burdened by his work as chairman.

Dr Kass was a controversial figure. He vigorously defended the dignity of the embryo, was sceptical of a pragmatic bioethics which signed blank cheques for technological advances in reproductive medicine, and promoted a highly cultured, holistic approach to ethical debate. Unlike previous government bioethics commissions, under his watch the Council acted as a brake on technological change — which many scientists and other bioethicists found increasingly irritating.

He was also criticised by his opponents for speaking forcefully on behalf of President Bush’s policy on stem cell research. “I think Leon went too far to engage himself in the politics the Council considered, writing newspaper op-eds and going on the think-tank circuit,” commented bioethics Arthur Caplan.

Kass’s successor on the Council will be the highly respected Dr Edmund Pellegrino, a “conservative” Catholic bioethicist who is a former president of Catholic University. Even the editor of the American Journal of Bioethics, Glenn McGee, accorded him gushing praise and said that he would be “no one’s stooge”.