Clones. Brain implants. Genetically engineered sports cheats. Members of the President’s Council on Bioethics have chewed on a steady diet of science fiction favorites in the panel’s first four years. In pondering technologies not expected to bear fruit for years, the council, led by American Enterprise Institute fellow Leon Kass, has defined its mission as being a search for a ââ?¬Å?richerââ?¬Â bioethics, concerned with preserving human dignity amid the advance of biotechnology.