Humanity has been slicing young penises for thousands of years.
Some parents do it for religious reasons, some do it because the doctor advised them to, and some do it because the father insisted his son be a spitting image of him.
If you're a new parent considering circumcision, here's a tip:
Your son's penis is not your property, it is your son's property, and you have no right to have it mutilated against his will.
It doesn't matter whether it's for medical or religious reasons, to carve off part of an infant's penis is psychotic behavior. Circumcision is maiming your son for life. We're born with foreskins for a reason. If your son one day decides he doesn't want it, he can have it removed of his own accord. It's not your fucking call to make.