The unified theory of why ?
Once upon a time man had no mate, more adams were cloned to take care of the earth. Then adam(s) were listless, One was chosen and after choosing no particular animal to mate with, a woman was cloned from a rib. After laying with woman once, Adam found he had 2 brains, The big one in his head and the little one in his dick. 9/10 times the little dick-brain overruled the big reason brain. woman came with a (fruit) to eat that they were not supposed to take. She offered it, Adam said no at first and then her swinging tits and ripe mons mesmerized him and little dick-brain said take a bite and then you get pussy. He took a bite and both brains got blown.
Moral - dick-brain is wrong 9/10 times.