[mvpel]

Depends on your culture as to how long it's been "firmly established."

http://www.hesston.edu/academic/FACULTY/DWIGHTR/SOC202/powerpoints/kinship/tsld027.htm

[NutCrackerBoy]

I read a tiny bit of your link. When they say 16% of cultures are monogamous, or whatever it is, what is the sample of cultures? Is that counting a tiny African tribe as one culture, and Europe as one culture?

Our culture and most of the world's major cultures are monogamous and have been for a thousand years or more. Will you please concede the point?