Margaret Sanger (1879–1966) was the most prominent leader of the birth-control movement. Her tireless dedication to her ideas enabled her to pursue the legalization, development, and distribution of birth control devices from 1914 until her retirement in 1959. She led the movement almost constantly, all the way from her first challenges to the Comstock Law, which forbade the distribution of information regarding contraceptives, up through the creation of the birth-control pill in the 1950s. She was the founder of Planned Parenthood.

She grew up in a freethinking household. Her father, Michael Higgins, earned his living carving gravestones for a Catholic cemetery. Nonetheless, he was a radical who apparently sponsored lectures at Corning by national figures including land-reform campaigner Henry George and Robert Green Ingersoll, the leading agnostic orator of the day. The work that built Margaret Sanger’s fame began in New York City, but her roots are firmly on the Freethought Trail.