Reddit reviews Sex, Time and Power: How Women's Sexuality Shaped Human Evolution

I don't recall the exact reason - I read it in Sex, Time and Power: How Women's Sexuality Shaped Human Evolution - but I think it had something to do with women garnering more power if they could conceal when they were most fertile. And I think it is fairly obvious that human females advertise their fertility less than other mammals - smell is less strong, etc.

EDIT: From Amazon comments ... "In particular, sex was an act which carried potentially fatal implications for prehistoric women. Because the stakes were so high, [women] took control of their own sexuality; they could not afford to be as carefree as men."

If you're interested in this, I highly recommend reading Sex, Time and Power by Leonard Shlain. It's a very interesting read about how female sexuality helped shape our evolution. I don't necessarily agree with everything he suggests - he seems to theorize that female sexuality was THE driving force that caused us to evolve into humans. I always take those kinds of theories with a grain of salt. I highly doubt there was a singular force that caused us to evolve. Rather it was most likely a combination of several factors. However, it's still interesting to consider the impact that female sexuality had - it isn't something that's brought up often.

(As a side note, there's a chapter that goes WAY into detail about the menstrual cycle. I was reading it while on the train and had just started my period. I had to get off the train and dry heave. Seriously.)

(Another fun side note - the cover features a painting of Eve (naked) with a serpent. I was reading it in an elevator when a mother and her 9 year old son got on. The kid stared at me intensely, and when they were about to get off the elevator he said to me "That looks like a really good book.")