If you believe in reincarnation, I have an interesting perspective, try this one on for size....
When God tells you it's time to come back to learn the lessons you didn't learn the first time(s) you were here, you then pick if you want to be male or female, sometimes souls can't make the decision so they get stuck half way, meaning, even though they are in a female body, they are stuck in a male soul and therefore are attracted to women and visa versa.
Your theory is common in new Age thought and relies on the Ying/Yang, two halves, one always "male" one always "female" concept. It also explains crib death...allowing the newly re-arrived soul to exercise an exit strategy during a certain "escape period".
LOL!