Humans and some species of whales are the only known creatures on this planet to go through menopause - why is that? A new study asserts the reason that human woman go through menopause is because of, well, men being men.
Most conventional theories about menopause state that the period of infertility is a naturally-evolved mechanism to help women enter "grandmotherhood" to help care and nurse growing families.
"How do you evolve infertility? It is contrary to the whole notion of natural selection. Natural selection selects for fertility, for reproduction -- not for stopping it," said biologist Rama Singh who led the team that conducted the study detailing the theory.
The real reason, Singh asserts, is because human males have a tendency to migrate towards younger females. Call it a product of society, or simply instinct that young females have higher reproductive capabilities than older ones, men seem to have preferred the youthful offerings of the opposite sex throughout time. Menopause is merely an unforeseen byproduct of natural selection.
"In a sense it is like aging, but it is different because it is an all-or-nothing process that has been accelerated because of preferential mating," says Singh.
The dog-eat-dog world of Darwin's natural selection process seems to recognize that older women are less likely to reproduce, and after a certain age, stops fixing the genetic mutations that lead to menopause. If the woman is not selected as a mate, then why bother keeping everything running in tip top shape? At least that's what Singh and his team are saying the human body is doing.
"This theory says that natural selection doesn't have to do anything," Singh explained. "If women were reproducing all along, and there were no preference against older women, women would be reproducing like men are for their whole lives."
Of course, the million-dollar question is: do some species of whales also exhibit an incredible affection for younger females?
You can read the published findings in the journal PLOS Computational Biology.