That's more evidence than shows that sexual orientation is genetics, but that hasn't stopped that myth from being pushed. Since 'sexual orientation' is impossible to define, it is makes it impossible to prove it has changed. How many women does a guy have to sleep with to prove he is no longer 'gay'? There are guys that go on to live normal lives after being 'gay', but do they ever get rid of all their sexual fantasies? Probably not. A guy may hate his ex-wife, but he still might fantasize about her at times. Medical schools teach that everybody is gay to a certain level, and they push a scale from 1-6. We will never solve the genetics vs. environment debate in any behavior, but there should be no debate that both are factors. Does therapy change behavior? Of course it does.