Harvard Professor Edward H. Clarke wrote in a paper in 1873 that though women have the right to seek an education, it was not possible to do so and stay healthy. A proponent of the “menstrual disability” theory, he said that whereas male puberty came on slowly, female puberty came on fast, and the body is not able to do two taxing things at once. He advised against too much education for people who menstruate aged 12-20, elsewise the population would drastically decrease due to infertility. He proposed instead regular breaks and shorter study sessions, writing:

“A girl cannot spend more than four, or, in occasional instances, five hours of force daily upon her studies, and leave sufficient margin for the general physical growth that she must make… If she puts as much force into her brain education as a boy, the brain or the special apparatus (i.e., the reproductive system) will suffer” 

Not everyone agreed with his theories though, and contemporary critics believed he created this theory to prevent Harvard admitting female students. 

In his introduction to the book, Clarke insists that menstruation must be a central concern.