any engaged parent will figure out within a year if their teenage child is really transgender vs a drama queen vs experimentation. You don’t finish a combined middle high school in eigth grade as Ellen and start 9th grade as Jackson on a whim or as an attentention whore. No one does that.
Sure, I initially thought that “when you’re 18 you can start hormone therapy and gender affirming surgery.” It took me about 18 months to come around that I was the blocker and not my son. BTW, son has a good therapist that has been helpful.
It’s not even just for religious reasons. The vast majority of American males are circumcised, even though only a small minority belong to religions that have ritual circumcision. It’s purely a cultural thing.