That subtilely implies it’s a decision to view oneself as a different gender from what was assigned at birth, but it’s not entirely clear it’s a choice in every case. Edge cases in biology get wild and sex assigned at birth can be a near arbitrary decision. Ex: https://en.wikipedia.org/wiki/Chimera_(genetics)
Parents making major medical decisions has a huge precedent in a wide range of procedures with significant risks and consequences. Separating conjoined twins for example.
It is entirely clear that it can be the case, as proven by the existence of people "detransitioning".
It is also entirely clear that there have been parents (usually mothers) who wanted to have a trans child because it was cool.
>from what was assigned at birth
The passive voice language here is really bizarre. Who is doing the assigning?
>Separating conjoined twins for example.
This is not, in any way, comparable to a 12 year old taking medications that permanently sterilize them.