It is not a crime in other countries and has not been for a hundred years.
If it is not your patient, stay out their their treatment....If you don't understand transgender, how can you decide what treatment should or should not be allowed, here or elsewhere?...It is criminal for you to play doctor when it is not your patient. You should have no access to what treatment, medicines, hormones or surgery they get. They have a right to medical privacy. You do not have a right to interfere.
Not only do you have a right to interfere; where a child is involved, you have a legal mandate to interfere. It doesn't matter if the suspect is a respected MD, or psychiatrist or any other professional. If there is evident child abuse going on, the crime is to be reported & prosecuted. Drugging a child who is so mentally whacked out to be in such a state of delusional unreality as to deny what they see between their legs every time they pee, is criminal. Coercing that child with hormones to believe they are a gender that you inform them of in a waiver "you can never actually become" and then performing amputations on that person, no matter what age they are is ILLEGAL. A mentally impaired person, defined by their lack of touch with stark reality in any DSM (pick your favorite), cannot give consent to either a hormone protocol or surgery that only increases their delusion and physical impairment.
When this is happening to a child, in the US, if you are a professional seeing this happen you are mandated to report it. In some 18 states if you are just ANYONE, you are mandated to report it to authorities in charge of prosecuting child abuse.