It turns out, the sequencing of hormones in the mother's womb is what determines whether a person's physical body and/or brain structure is male or female.<quoted text>
Well yes the first homosexual had to come from a man and a woman mating. That does not mean he/she was born homosexual. Who your parents are is not the only factor in a humans environment.
There is no gay gene and there is no straight gene. You behave inaccordance within natural intent of your gender concerning your reproductive organs or you choose not to.
Lets see, what could the purpose of reproductive organs be??? LOL
It is an established fact that some physical females have XY chromosomes and some physical males have XX chromosomes.
So, now what? Are physical males with XX chromosomes actually male or female? Who should they be marrying? It seems either way you choose, you now have a connundrum;
If you say physical males should only marry physical females, then you'll have pairings that amount to genetic females marrying genetic females.
If you say genetic males should only marry genetic females, then you have what looks like on the surface to be a lesbian marriage.
Either way, they don't have a choice about who they are. Are you going to exclude them from marrying anyone and why should you have that right?
Just because you are stupid? I don't think that should give you extraordinary rights.