I should probably wait until you post the advantages, but...

... there's a possibility that menopause is linked to a longer life span. The specific evolutionary value of this is the preservation of knowledge across generations, which can mean survival for the tribe, including, of course, all of the women's offspring.

That particular piece of speculation comes from The Third Chimpanzee by Jared Diamond. You'd probably find it an interesting book, given that he spends maybe a third of the book discussing the evolutionary consequences of various human sexual behavior patterns.

Kiralee