Well, I know that in the African equivalent, which actually takes place when the child is fifteen or so, the foreskin is hacked off with a rock. If you live, you are now a man.
Oh, wait, I remember. The purpose of circumcisions was to mark out Jewish people from all others. It says so in the Bible somewhere. Or so I'm told - I've never actually read the Bible, despite actually trying to two or so times.
I don't think I ever got past the first ten pages.