There have been Trans people as long as humans have walked this Earth.
There is very, VERY, good, peer reviewed, research that indicates Trans is a form of Intersex at the sub-chromosomal level ie gene switching.
But hey, close minded, predudiced bigots, with ZERO genetic education, are going to continue to bigot.
I thought we lived in the 21stC.
Apparently not.
I despair.