If I had a boy who wanted to be more girly I would definitely let him take estrogen and T blockers. If he really seemed to want it. Why not? The effects aren't permanent.

If I had a girl who wanted to be more boyish though that would be a tougher decision. Being female is a lot better than being male unless you live in India. So I may not agree to that.

I would not allow my child to get a sex change operation though because ultimately that doesn't really matter. It doesn't make any fundamental difference except for actually having sex which presumably they are not doing yet. If they really want the surgery they can pay for it themselves when they are adults. Hormones though are not such a problem.