Not all scientists, however, are so quick to dismiss the import of women's monthly bleeding. Margie Profet -- a young, maverick evolutionary biologist from the University of California, Berkeley -- made her entry into the scientific forum in 1993 by asking a question no scientist had thought to ask since Hippocrates and Galen: "Why do women menstruate"? Profet's findings, painstakingly detailed in an article for the renown Quarterly Review of Biology come remarkably close to her scientific forbears. Profet argues from an evolutionary standpoint that there must necessarily exist a functional purpose for regular menstruation or it would not have endured the mutations of our evolution; Menstruation must offer some advantage for human survival or it would not have survived itself. It is not likely, Profet maintains, that our bodies are so inefficient as to permit a monthly expenditure of energy without a concurrent gain.
Profet noted at the outset that menstrual blood differs in composition from that of regular blood, most notably by containing immune cells called "macrophages". These cells are able to combat the presence of pathogens present in the uterine cavity. It is from this observation that Profet establishes her hypotheses: "Menstruation functions to protect the uterus and oviducts from colonization by pathogens" (p.335). Regular bleeding is a regular cleansing, in Profet's estimation, keeping women's reproductive organs free of contaminants. And from where do these pathogens come? From men, of course: "Sperm are vectors of disease" states Profet unhesitatingly (p.335). Sexually active women require a method by which to protect themselves from potential infection caused through intercourse. Menstruation is nothing less than a sign of the ongoing war of the sexes -- the natural means through which women protect themselves from men.
The enforced cessation of menses then, from Profet's perspective, would be harmful to a woman's health rather than beneficial -- "The uterus appears to be designed to increase its bleeding if it detects infection….Thus artificially curtailing infection-induced uterine bleeding may be contraindicated" -- since it interferes with her body's natural capacity to defend itself against pathogens (Profet, p.355).
