There was a period of about 2 or 3 years when my cousin’s son wanted to wear wigs and jewelry and play with girls’ toys. He was 6 or 7 at the time and his parents (my cousin and her husband) had just gone through an ugly divorce. He eventually grew out of it. If my cousin had bought into this BS, the medical profession would have psychologically and physically maimed this kid with their treatments, perhaps permanently.
When WBill Jr was just a tad, he wanted to wear a dress to school for some costume day. Nothing weird, or transgender about it, he just thought it would be a goof, I think.
Still, being the Dad, I said, "No". And that was that. He was mildly annoyed for about 5 min, then we all moved on with our lives. No therapy needed for anyone involved.
Frankly, I think that these cases are what end-stage Munchausens by Proxy look like, only in a socially acceptable form. At best, they're caused by parents who just don't love their kids enough to tell them, "no.".