Archaeoptryx
Even if it's not religious, circumcision makes for a much cleaner p***s, what with how lazy boys are with showering.
It's a common myth that an intact p***s is unclean. The truth is it's not any dirtier than a cut p***s or a female's labia. Most men never have a problem with it and most parents care enough about their kids to make sure that they have basic hygiene.
And frankly, if you think foreskin is gross you must think that labia are the most disgusting thing on the entire planet. They easily trap more fluid, odor and debris!
Speaking of female genitalia:
If tradition justifies altering male genitals without consent, why not the same for female genitals?
I know that most female genital cutting actually destroys a woman's ability to expereince pleasure and that most male genital cutting doesn't*, but the principle is still the same. You're altering a private part of your child's body without their informed consent because of your religious and cultural traditions. Your child is being... "modified"... to put it gently, because you feel that your religious beliefs suprecede their right to bodily domain.
And besides, there's no medical reason to circumcise, either:
Reproductive Health Reality Check | Gimme Some Skin
*(Some forms of FGM do not destroy the clitoris but instead remove the inner labia and clitoral hood, the latter of which is the female foreskin)