French biochemist Etienne-Emile Baulieu (1926-), who has spent more than thirty years researching hormones and co-founded the International Society for Research in Biology and Reproduction, soared to international notoriety in the 1980s with one of the most controversial medical breakthroughs of recent times--the invention of RU 486, known as the "abortion pill." RU 486--now known as Mifepristone--is an "antihormone" which blocks the effects of progesterone, the hormone that allows an embryo to develop in the uterus. Once this happens, the fertilized egg and uterine lining separate from the uterine wall and are expelled through vaginal bleeding.

After developing the steroid in 1980, Baulieu and his colleagues at the French pharmaceutical company Roussel Uclaf performed numerous tests on animals and found the drug to be nontoxic. In 1985, extensive tests on human volunteers were carried out in France, Great Britain, Holland, Sweden, and China. RU 486 was found to be safe and to...