The only permanent punishment should be death. I don't see what is wrong with such a penalty for pedophiles, but either move your bowels, or get off the toilet bowl. Mutilating anyone should not, under any circumstances, be an acceptable punishment. As for the chemical castration, it is the same principle. If this treatment is not permanent, what is the point, even if you stipulate the acceptability of castration? And beyond that, doesn't an awful lot of child sexual abuse consist of more than sticking a penis in the kid? That is the only act castration would prevent. I can't imagine the sort of sick freak who goes for kids in defiance of all taboos and laws is going to lay off because he can't get it up. It would seem to invite such people to channel their urges into other outlets (torture, etc), none of which would be notably healthier for their victims.

All in all, it is the parents' responsibility to protect children from stuff like this, and whenever I hear of some sort of Concerned Parents group or individual whose sole reason for speaking on the subject is his parenthood, endorse such punishments, I get the impression of people who want to be able to slack off on their own responsibilities.