In the early 1920s, Austrian scientist Ludwig Haberlandt published a paper suggesting that hormones could be used as an effective means of contraception in animals. While it is unclear, he may have soon after tested a hormone preparation in clinical trials, despite heavy criticism from colleagues who considered contraception to be taboo. Haberlandt’s work, however, came to an abrupt end with his suicide in 1932. Two decades passed before further clinical trials of hormonal contraception were conducted in humans, and then largely at the urging of social activist Margaret Sanger. The first birth control pill was approved in 1960, in the United States.