I definitely don’t think parents *always* know best. Any honest parent of a teen or young adult will tell you they make plenty of parenting mistakes, and are sometimes proven wrong. I do think that parents often know better than therapists or other stranger-adults who don’t always have the best interests of the kid at heart, to be honest. Nor do those other adults have the benefit of having lived with the kid and knowing how sudden (or not) the desire to “transition” may have been, what other kinds of longstanding issues there are, and so on.

The thing is, parents and kids often become estranged—sometimes for years–because of differences of opinions (or values) about all sorts of things. Many of the people I know were estranged from their parents as teens or young adults–and this was before medical transition was a thing. Later, they reconciled. Speaking only for myself, most of the things my mother (the main player in my case) disapproved of turned out to be things I ended up agreeing with her on later.  Your mileage may vary, but estrangement between parents and teens, especially when the parents see the course the kid is trying to take as potentially harmful, is pretty common.

All of this said, it’s my personal opinion that medical transition should be a decision taken by an adult, preferably one over about the age of 25 when the brain’s decision-making capabilities are more mature. I honestly don’t see how anyone who has lived through the tumult of adolescence can be in favor of adolescent brains making permanent medical decisions that will have to be lived with forever.