For the most part I agree.
But there's no way a kid that young can make that kind of decision. Even if your 6 year old likes to play with makeup or play dress-up, I see absolutely no reason to send him to school dressed like a girl.
Well, I see no reason to send kids to school, period. But if you approach it from the perspective of the child, it's you imposing your will and your preferences onto them over theirs.
That's just asking for confusion, ridicule and abuse.
Not really, is it likely to happen though? Yeah, but that's their experience to deal with. Kids can be bulldogs and if you don't conform, you're going to get ridiculed. That's one of my big issues with public education, forcing groups of people together against their will does not make for a good social experience.
So on one hand you have a child who's expressing free will to dress however he/she wants (something certainly not against the NAP), and on the other you have the negative consequences associated with non-conformity. If the kid is 6, I'm sure he's old enough to understand what cause and effect is, and what is likely to happen based on his actions. If the kid is willing to take the ridicule, so be it. Conformity is over rated.
I can't see how this lifestyle is 100% decided by the child with no influence from the parents. A child is going to wear the clothes you buy for them.
I'd influence them to the point at which I let them know what is likely to happen for dressing up as the opposite sex. If they're OK with that, so be it. I'm of the belief that we don't "own" our children. They're independent, separate human beings with their own brain and ability to make decisions on their own. We're just here to guide them. But I believe being consistent in libertarian philosophy (self ownership & the non-aggression principle), means applying those same concepts to child rearing.