Nettie Maria Stevens was born in Cavendish, Vermont, on July 7, 1861. She was an outstanding student, who finished high school during a time when most women never even reached that educational level. Still, her career opportunities were limited. Stevens earned her living as a school teacher and librarian, as did most unmarried women in the late 1800s. But unwilling to spend her whole life teaching high school, she sought further education. Since most universities did not admit women, she enrolled in Westfield Normal School, a teacher's college. After earning her certificate, she spent the next thirteen years working and saving in hopes of attending one of the country's few co-ed universities.

In 1896, she entered Stanford University in California, where Stevens received her master's degree in 1900. She was eventually attracted to Bryn Mawr College, where she conducted her postgraduate work under Thomas Hunt Morgan. (Another distinguished member of the faculty...