Before the role of the male in reproduction was understood, men might have been in awe of women— women bled without pain or injury, in their menstrual periods — and most importantly — mysteriously, their bellies swelled, life stirred within them, and new humans emerged, and milk to nourish these new humans filled the breasts of mothers. Miracles ! It was thought that the reason for the penis was only to widen the birth canal — after all, not every act of intercourse results in pregnancy. When men understood that some component in their bodies was essential to baby-making (I think women understood this much longer) — wow — suddenly they were glorifying penises left and right — setting up obelisks and towers — and using their generally superior physical strength to dominate women, and build a culture of male power. (These cultures were mostly herding cultures — hunter-gatherers were/are more egalitarian — the concept of dominant-male cave-dwellers is a modern fantasy — our complex agricultural societies were made by herders who settled down to farm) For awhile there, men insisted that the entire potential child existed in the sperm, and women were merely a fertile field in which this seed is planted — like a grain of wheat planted in a field of good soil — science proved this to be silliness.