Why do women menstruate? | Pharyngula
http://freethoughtblogs.com/pharyngula/2011/12/21/why-do-women-menstruate
I suppose we could blame The Curse on The Fall, but then this phylogeny would suggest that Adam and Eve were part of a population of squirrel-like proto-primates living in the early Paleocene. That’s rather unbiblical, though, and what did the bats and elephant shrews do to deserve this?