wow, intelligent speculation and several posts profanity-free ...
I actually found this site searching for pheromones and their possible link to human sexuality -- it stands to reason that they play a part in so-called 'normal' sexual behaviour, they play a part in alternative sexual behaviour.
The human vomeronasal organ, or VNO, is located in the nasal passages where the olfactory receptors are. It is relatively small in humans, and exactly to what extent it influences our behaviour is, naturally, in need of further study.
So far in my own research it seems that everything bubbles down to brain chemistry and its subsequent effects on who we are. Research points to pheromones as influencing estrous or fertile cycles in women (synchronicity among female companions, or increased regularity of cycles with exposure to male pheromones). It is possible that all human sexuality is attributable to pheromone receptors and their pathways in the brain.
Axons can sometimes grow to adjacent areas of the brain -- it explains the foot fetish, as the somatosensory neurons for the genitals are adjacent to those of the foot. Maybe where exposure to male pheromones causes aggression and frat-boy baudiness in 90% of men, causes arousal in the other 10% (I vaguely recall some hazy statistic that 10% of the population is homosexual). Any genes responsible for homosexuality are like many of the others they have discovered, such as the gene for alcoholism -- it may or may not be 'activated' by environmental factors.
I would be very curious to see if the VNO is more developed in people who cannot (or do not) rely on visual erotica. Blind people fall in love - is their pheromone sensitivity more acute? What about cultures where physical features are more homogenous? Is our VNO 'devolving' because our culture relies so completely on visual sexual attraction? Might not pheromones be a better chemical indication of compatability than visual attraction alone?
More and more I think homosexuality is merely a state of being. The mechanics behind it are fascinating as is any aspect of human behaviour (such as it is). How true that so much of the research is not so much out of curiosity, but with the intent of finding ways to eliminate diversity. How much money is spent researching finding the gene that causes the Great Apes to murder one another en masse?