I think we do know - homosexuality is a defect of biology. All humans start off as females. We 'become' male or female. Sometimes the transition doesn't work. We see hermaphrodites. Their body is confused.
They have no choice - they were born that way.
But that doesn't mean people can't be conditioned or trained to accept a defective lifestyle.
I've heard this crap spouted only by homosexual activists, but never by real scientists. Do you have an objective source?
The sex chromosome, XX or XY, determines sex. Saying that "all humans start off as females" directly contradicts this proven fact.
Hermaphroditism is different from homosexuality. Hermaphroditism is caused by biological factors—homosexuality is not!
Hermaphrodites usually are treated surgically soon after birth, and also may receive hormonal therapy. Then they usually act and feel as either males or females—not “intersexes” or “gays”.
It is a mental illness the same as bestiality, pedophilia, necrophilia and all the other sexual illnesses.