Well, Yerusalyim, I already mentioned the reason why I was against the very young having plastic surgery (health reasons). Do you think that even if a parent did give consent for a child to get plastic surgery that the supremecy of parental consent ought to be the only thing that factors into allowing the procedure to happen? If the Hare Krishna's were not a dangerous cult that literally could cause you bodily harm, I would definitely disagree with a parent tiranically deciding that their child should not have the freedom to choose their religion (or to flip it again: if you decided that your child should be allowed to be a Hare Krishna, would that make it OK, since you've given the all important parental consent?)
Of course, you do make a valid point about where a line should be drawn, and it's certainly not my intent to imply that a parent has no right to tell their kid what to do (e.g.: help out around the house, do homework, TV regulation), but the right of the parent to tell the kid what to do only extends so far as it does not bring harm to the child (so if for some impossibly odd reason making a child do his homework would cause him some sort of irreparable harm, then I don't think the parent should have the right to make their child do it). In the case of a parental consent for abortion, for some kids letting the parents know about it could bring harm to them.
But as I stated in a previous post, the abortion case extends over to yet another principle, namely whether or not a parent has the right to override a child's reproductive rights, and in the process potentially adversely affect the child's life well beyond the time they'll be with their parents. Should a parent have that much power over not only a child's adolescence, but also the child's adulthood? Should the parent be able to single-handedly overrule a child's legal right to abortion? For me, the answer is clearly no (if the parent was not able to convince their child of the reasonableness of their anti-abortion attitudes for the preceeding 11-17 years, then they should have tried harder ). Not when so much is at stake in the life of a child.