Why put people into strict boxes like 'straight', 'bi-', or 'homo-' when these are purely arbitary placing. A person can be attracted to the opposite gender today, the same gender tomorrow, and both on Wednesday.
Certainly there are marked differences in the way women think from the way men think, but sexual attraction does not take the gender of the attractive one into account at all. Many people will hotly deny this at first, saying that they are one or the other, but if you just sit back in the corner of your mind and scan the people who wander past your view, you must eventually admit to yourself that there are people of your gender and the opposite to whom you might, just maybe might, be sexually attracted to. Under the right circumstances.
It's one of those polyamorous things which make life so much fun.