One can raise a lot of eyebrows and ire by offering mechanistic biology, dumb and billions of years amassing its complexities, as an explanation for any consequential difference in mating success. 50 pages into Louann Brizendine's book "The Female Brain" [which, plodding reader that I am, I will eventually review] it has become believable to me that hormones alone can account for much behavior by rewiring that spaghetti bowl of neurons that is the seat of behavior. I insist that if you pay any attention at all to this post, you go read at least the abstract of the paper. I will tease you with the most controversial claim about the findings:
...Nor are our results explained by after-birth social factors (females growing up with similarly aged brothers) because females born with a male co-twin have reduced success even when their co-twin dies shortly after birth and are raised as singletons after birth. Our findings suggest that hormonal interactions between opposite-sex fetuses known to influence female morphology and behavior can also have negative effects on daughter fecundity and, hence, maternal fitness, and bear significant implications for adaptive sex allocation in mammals.When you consider the social pressure, the weight of convention and community expectations around marriage and having children, and you put that together with the crap shoot called conception which produces the people on whom these expectations weigh, it is a wonder we don't have more feminists, ... or more suicides.
When some one figures out a way to get clean and meaningful data about which in-utero effects alter male behavior [Anthony Bogaert has tracked down one phenomenon but there are perhaps others] so that we don't have a lot of whining "but you didn't study my situation", maybe we could all just lighten up on what people are "supposed" to do with their lives, reproductively speaking.