Developer of 'the pill' Djerassi dies at age 91

Carl Djerassi, an Austrian-born chemist who helped to develop the birth control pill before becoming a playwright and novelist, died in San Francisco on Friday at the age of 91, his family said.

Djerassi, professor emeritus at Stanford University, was the leader of a team of researchers in Mexico City who synthesized a derivative of the hormone progesterone in a form that women could take orally. The breakthrough in 1951 became the basis of some of the first pills to prevent pregnancy.

"The pill", as it became known in popular culture, has been credited with fueling a radical shift in sexual mores and changing the role of women in Western society.