I don't know what the answer is to the sexual orientation question; whether it is genetic, a choice, or a mix of the two. However, I will throw my own first hand observations out there. One of my good friends was a lesbian from high school through parts of college. She had a few girlfriends and that was what she was attracted to. I dated her best friend, so we hung out a lot. She broke up with her long time girlfriend and did not have a relationship for a few months. Her next relationship was with my best guy friend and they dated for years. To this day she is still straight and dating guys, she no longer has an interest in relations with another female.

Either way she's still a friend and I honestly think she chose to no longer be a lesbian. It really was her choice.

Also, living in Southern California and growing up near Hollywood it seemed that people were changing partners left and right, male or female. However, we all know that area is not the most normal of places.