Menstrual taboos are old. But not all societies view menstruation negatively.

Menstrual taboos are found in the Quran:

“go apart from women during the monthly course, do not approach them until they are clean” Quran 2:222,

And the Bible (among others):

“…in her menstrual impurity; she is unclean… whoever touches… shall be unclean and shall wash his clothes and bathe in water and be unclean until evening” Leviticus 15

But, WHY?

The origin of negative menstrual taboo is still debated. Freud said it was our fear of blood. Allan Court argued the taboo began, in part, because early humans found menstrual blood to be soiling. Anthropologist Shirley Lindenbaum theorized in 1972 that taboo was a form of natural population control, limiting sexual contact with “pollution” stigma. In 2000, Historian Robert S. McElvaine coined the term non-menstrual syndrome or NMS to describe the reproductive envy that led males to stigmatize menstruation, and to socially dominate women as “psychological compensation for what men cannot do biologically”.