They also believed that every time a man ejaculated, it hurt his health, his IQ-Is that where the term dumbf**** comes from?
I cannot stress enough that these scientists weren't crackpots, they were internationally respected, influential theorists, and all this was 'common knowledge', taken for granted and believed by pretty much everyone in the health and science fields. And the whole 'woman as vampire' and sex as contaminating and weakening for men (and whole races) was picked up by artists and writers, and shows up in many books and paintings from 1890-1940. Both works considered masterpieces and potboilers show the influence of these theories.