Through reading I've noticed that when a woman is pregnant her significant other (assuming its a male), his sex drive does one of two things, either it plummets, or it skyrockets. Which had me thinking, could that be a determinant of whether or not the child is biologically his. Think about it, at some level, whether biologically or subconsciously, the guy probably knows, if his sex drive plummets he would subconsciously know the child is his because he no longer is interested in sex until said child is born. However if it has skyrocketed he probably subconsciously knows that the child is not his, therefore he goes on a biological rampage in order to plant his seed. On an animalistic level it pans out, when i was younger i had many animals, and I'd observe, the male animal that inseminates the female is not concerned for said female, he goes out to look for another to impregnate, however the animal that didn't, sticks around and literally tries to get with the female animal no matter how many times she turns him down. Just a thought, lemme know what you guys think. I could be wrong of course but it came to me while driving to work, thought I'd share