The thing with such studies, is that they seek to understand an effect after a cause.
So studies that seek to understand the cause are always philosophical, and therefore speculative and contentious.
I'm just speculating that changing socio-psychological attitudes towards recreational sexual activity, have affected and changed physiological development in some specimens, in some societies.
Whether or not this is indicative of an irreversible phase of species evolution, will become apparent, if and when it has become apparent...Whence we we will be able to pay certain clever people a decent salary to study and understand the effects.
I suppose that we could also surmise that the persistent socio-psychological influence of religion in certain societies has similarly effected the human brain.
Has there ever been a comparative study done?
Whereby we can separate the human species into two distinct classes... Homo-theins and Homo-athiens.
Whereby we might further sub-divide into Homo-theins-transsexualus, Homo-theins-nontranssexualus, Homo-atheins-transsexualus or Homo-atheins-nontranssexualus.
Or even Homo-theins-nontranssexualus-MAGAnoides and/or Homo-atheins-transsexualus-libertoides.
And so on.
All that respected scientists need to do, is spot the relevant white matter connections and cash their salary cheques.
Yes, I am fully aware that salary cheques, these days are metaphorical.
Yours sincerely.
Homo-atheins-nontranssexualus-moderatoides-nonsenileidae...(I think that I still have the white matter to prove it....I just need a respected scientist to find it).