ANCIENT GREECE

Menstrual blood is the equivalent of semen

Aristotle (384-322 BCE) was a Greek philosopher with a lot to say about menstrual blood. He believed that sex in humans was determined by the warmth of the womb while a foetus was gestating. His theory went that all foetuses have exactly the same organs, and a warm womb would ‘push out’ the genitals in a way that cold wombs would not. So a penis was an external vagina, ovaries were under-developed testicles, and so on. And it followed that menstrual blood:

“is the analogous thing in females to the semen in males”

He believed that babies were made by the mixing of menstrual blood and semen. According to his theories, semen was made from blood and as those who menstruate don’t make semen, as a result they have excess blood in their bodies which had to be discharged via a period. If someone ever stopped menstruating, he said that their body would try to get rid of the blood in other ways such as through nosebleeds. 

(IMAGE CAPTION) A marble Roman copy of a Greek bronze bust depicting Aristotle by Lysippos c.330 BCE, Palazzo Altemps, Rome, Italy.