I thought it was started because the old testament says Abraham offered the foreskin of his sons as an offering to the gods
Discussion
There are early reports of explanations and appeals for the reason I gave, but part of the idea may have made it into religious text because of that or vice versa. I’d be curious on the chicken/egg situation there.
Either way it should be illegal to mutilate baby boys, when you turn 18 you can cut your own Weiner however you want!!