This is a good and important point. The problem comes when/if there is a way to realign gender and sex early on. Is being trans a "treatable problem" at that point, like cystic fibrosis, or a lifestyle choice? Certain members of the deaf community resist treating deafness in their children. Parents can and do provide consent for their children, so if the most effective solution to a gender/sex discrepancy is in-utero or early childhood therapy, would you deny it to someone? Kinda reminds me of some of the plots on "Orville" with their sex reassignment society (though they never really discuss gender, presumably the procedure fixes this?).