Yeah,if there truly was overwhelmingly evidence for the brain argument then TRAs would demand medical staff to use MRA scans to prove whether someone was trans or not.Yet i've seen some legit claim that people should translate regardless.Honestly, i don't think we'll ever find any brain evidence of transgenderism because really there's no inner feeling as to what it is be a man,women or heck even non binary.Which is another reason why i believe the second theory is going to be true.