Originally Posted by Tonberry
I believe monogamy becoming the norm is due to wanting to know who's whose child. There didn't use to be a way to tell who was the father otherwise, and when property started existing (in the form of land or whatever) and needing to be passed along, men would have wanted to make sure they passed it to their own children and not someone else's.
I believe that's the reason why monogamy was generally expected of women but not so much of males.
True to a degree. However, there are societies (the Ashanti of West Africa comes immediately to mind) where property rights are transferred along the female line, i.e. men inherit their mother's brother. Or women might own the land entirely whereas men own ceremonial equipment and uncles initiate their nephews into the secret men's societies or whatever. Property from an sociological POV is not a uniform concept as we in the West understand value.
From a strictly biological POV, men should invest in the children of their womb-sisters, for a lack of better word, i.e. women with whom they share a mother. Whereas before the advent of modern technologies of re-production, women always knew who was their child, men never really do. I think it's a trade-off between the avails of pregnancy and labour/security in the continuation of your line.
There are a lot of theories of 'monogamy' (most often single-standard) being the compromise between a woman wanting to have a strong male partner care for her and her offspring and a man wanting to impregnate as many women as possible somewhere in the dawn of time. I personally think these theories are way too biased by what we (think we) observe from modern and historical behavior standards. For example, these theories never explain why having an unrelated man take care of her and her baby would be so much more preferable for a woman than having a close relative be the man in the house (or the cave). Also, why a society would necessarily function better with multiple male-female couples than with larger family groups composed of women with men primarily affiliated with each other and their mother's/sister's house is never explained either.