I have sometimes wondered, how more likely a person inborn moderate qualities are impossible to be changed.
If one was talkative as a little child, it doesn't necessary mean that when one grew up and socializes not, one has "changed".
I believe the innate characteristics are still there. They were merely suppressed, transformed for good or bad, in mysterious ways.
However, as for as sinful characteristics such as homosexuality, I would say it is an already transformed nature, perhaps from a very passionate attitute, after the bombardment of pride, malevolent, anthropocentric notion, etc. As all men deserve not God's grace since fall.
Therefore, I am intrigued to discover this "fingerprint" of a person's soul, how he was when he was a baby, comparing his own testimony of his past and the truth of it, analyzing it with the present behavior, etc.
One terminology in psychology that deals with a small part of similar subject would be Trauma.