Kind of goes against Darwin's theory doesn't it?
Under Darwin's theory if you were born gay you would be a dead end.
The current thinking in the scientific community is that homosexuality is likely caused by a complex interaction of psychosocial, environmental and possible biological factors. And the two leading national psychiatric and psychological professional groups agree that, so far, there are no conclusive studies supporting any specific biological or genetic cause for homosexuality.
In sum, there is no scientific or DNA test to tell us if a person is homosexual, bisexual or even heterosexual for that matter. And since nobody is "born gay," it's clear that sexual orientation is, at its core, a matter of how one defines oneself not a matter of biology or genes.