Why do many who believe that “all are born sinful” hold that “none are born gay or trans”?

Many Protestants, though not technically or officially [Reformed](http://en.wikipedia.org/wiki/Calvinism) , are nevertheless strongly influenced by Calvinistic theology; as such, they espouse the doctrine of [total depravity](http://en.wikipedia.org/wiki/Total_depravity) , teaching that all men are born under the power of sin (Psalm 51:5). However, a large part of them are also [politically active](http://en.wikipedia.org/wiki/Christian_right) , and I couldn't help but notice that this important segment (ascribing to [conversion therapy](http://en.wikipedia.org/wiki/Conversion_therapy) and associated with the [ex-gay movement](http://en.wikipedia.org/wiki/Ex-gay_movement)) also holds to the notion that [no one is born gay, trans](http://en.wikipedia.org/wiki/Biology_and_sexual_orientation) , etc., but rather, they embrace certain [discarded psychoanalytical ideas](http://en.wikipedia.org/wiki/Homosexuality_and_psychology) about the latter being a product of upbringing; in other words, of [nurture, rather than nature](http://en.wikipedia.org/wiki/Nature_versus_nurture) . Granted, I am not exactly arguing that all sin is inborn, and that no vices are learned or (self)taught, but the (religious) zeal with which they (communally) cling to this opinion seems to border on dogma. My bewilderment stems from the (apparent or perceived) contradiction between the two views. Am I missing something? If so, then what?