Sexual orientation is a psychological fiction. It is not a fixed and immutable part of one's body, like a bone (which is also capable of growing and changing, btw). One's "orientation" is a record of one's experiences and a point of view about where one intends to continue accruing experiences. But people can and do change. Having worked in the arts for many years, I have seen many people with this preoccupation about gay sex encounter an experience or undergo a series of insights from which they set about to change, and did change, and stayed changed -- some with more consistency than others. The brain is fluid, not concrete.
"Be ye transformed by the renewing of your mind."
nice post