It worries me the most when kids are deciding on getting their sex changed, started at a young age. And I heard that there is a prop being voted on in some states that would make it legal for children to ask for hormone therapy and other such things without even having the parents permission.
Kids shouldn't be worried about this stuff growing up. If they want to be the opposite sex, or identify as something else, go for it, but don't change your body until you know for sure it's what you want. And you have to weigh the risks of it as well. Like a few posts above with the woman transitioning into a man. It may not always go the way you want it to.