OK, I'll give you that it is a stretch to go from one person being unable to support an argument with any scientifically valid evidence to concluding that no scientifically valid evidence exists. But now you come on and also provide zero scientific evidence to support the proposition. So we are at two. This time, I'll try to avoid the stretch and simply say that zero scientifically valid evidence has been presented in this thread to support said proposition.
And you know what else is a stretch? This:
"Logically, I'm not sure what's left if you take away monogamy and serial monogamy. Either polygamy, which seems unlikely, or just sex with zero pair bonding leaving the females entirely to raise the kid. Also seems unlikely, and would suggest that monogamy is even MORE unatural for humans if our biological hard-wiring is for sex with no pair bonding at all."
That is a huge stretch.
Polygamy seems unlikely because . . . ? No reason given
Zero pair bonding leaves the females entirely to raise the kid? Not even remotely true
Also, for those who like to present the "Male-female monogamous bond for 6 years until kid reaches some level of autonomy followed by switch in 6 year partner" hypothesis - what happens with all the kids produced by that pair during that 6 year period? Most likely, the female at the end of those 6 years has a 6 year-old, a 4 year-old, a 3 year-old and a 1 year-old (and is currently pregnant). Only the oldest one has reached the semi-autonomous maturity level that folks cite. Doesn't seem to mesh very well with the neat picture people try to paint of this arrangement.