“According to recent DNA analysis, through the history of the human race about 80 percent of the women reproduced, but only 40 percent of men reproduced.”
quoted from A Billion Wicked Thoughts: what the world’s largest experiment reveals about human desire by Ogi Ogas and Sai Gaddam
I remember a primate researcher saying that human sexual dimorphism (in regard to the relative sizes of men and women) is consistent with our being the descendants of families of one father and two mothers. In a species that is primarily monogamous the males and females are much the same size and weight. Gibbons, an example. On the other extreme would be gorillas – big big male, several much smaller females.