I think like most things- it should happen when and if the child involved wanted it to- at what ever age- but not before they can say yay or nay. I always wanted mine done as a kid but i had to wait til i was 13 (about 6 years of waiting and pestering from memory) i do rememebr that it DID hurt a little- even with the numbing spray (they might use a stronger one on babies though) and now over ten years later i have taken them out because i can never be bothered changing them when i go out and i lost a sleeper and just never bothered to get another one...

I guess i am saying i will be somewhere in between- i wont make my child wait for no reason (like mine did) and if she (or he) wants to peirce something they can go for it and enjoy it while they want to!! But i wouldnt do it to a baby who couldnt say if they WANT it or not!!