You will probably cause more trauma to the child by forcing him to be something that he/she is not.
what makes people think they have the wrong gender.
I wouldn't let my kid decide if it wants to eat Cheeseburgers all day everday for lunch, so why would you let a child decide if it's in the wrong body at age 6 that's just dangerous and crazy. Some of those "treatments" are not reversible for example if you block your kid's puberty or get a gender reassigment surgery at an early age.
I don't hate trans people and i can accept the choice of "changing" gender when they are of legal age and can decide on their own after a thorough psychiatric evaluation to take HRT and / or get a gender reassignment surgery, it's a mental illness according to medical science with the remedy to the the symptoms mostly being a transition to the other gender.
It's in the DSM-5 ( Diagnostic and Statistical Manual of Mental Disorders ) as Gender dysphoria https://en.wikipedia.org/wiki/Gender_dysphoria .
Please don't let a Child decide if it wants to transition to another gender, when they can't even decide what toy to play with for example.