As long as a kid is a kid, and not an adult, and as long as any therapy is not tyrannical, not abusive, not physical and includes and requires agreed cooperation by the person receiving the therapy, the state is wrong, morally and scientifically, to conclude that self-identification as “gay” is a pre-concluded process from which nothing in nurture can alter, as SCIENCE cannot identify a “gay” gene or a set of “gay” genes that genetically determines “gayness”.
There may be epigenetic factors, even in the womb (that affect nueral networks and/or how their manner of development), but science cannot it knows there is any definite epigenetic factors.
That leaves nurture as the best possible location for any “gay” development factors. That also leaves the possibility that nurture can somehow represent some factor extremely early in child development, even in infancy, without any “gay” identity to it at the time. That also means that factors arrising from nurture much later in child development can be involved. That also leaves the possibility of any of the above being true in general but each only true in some cases and not in others. That leaves the possibility that what nurture has already done might be undone, in some cases, and might be more difficult to be undone in others.
However, altogether it all still leaves nurture, not genetics, as, somehow, scientifically, the most likely route by which “gay” self-identity is established, and especially for the immature person (kids and teens) it - nurture (parents, family, relationships, education, thinking), including “therapy”, represents a scientifically legitimate route for parents, kids and teens to question that identity.
However again, I will only add, that while we are speaking of mostly immature persons in this case - kids and teens - “therapy” to change “gay” identity in adults has not had much success and has been abandoned by many former advocates of it. Maybe, just maybe, the failure was - in some cases - that no legitimate therapy was possible, offered or tried at an earlier and immature phase in life.