abnormal behavior.
see prison population behavior.
can a thief stop stealing? that behavior changes.
It is really simple. One behavior is biologically normal and produces results which society rewards.
The other does nothing for society.
Can a thief stop stealing? Insofar as stealing IS a conscious choice, yes.
I have no idea what that has to do with homosexuality. I suppose they could be celibate, but that would not make them any less gay would it?