Interesting. I wonder where this statistics "bisexuality is rare, men are almost always either gay or straight" comes from, because there seems to be a whole lot of hidden male bisexuality around. My husband is in a gay web community and there are many "straight" men looking for m/m sex without telling their wives.

So my assumption would be that most such men in such a survey would check "straight" even though they e.g. meet men for blow jobs, because they don't see themselves as bisexual (much safer for them, their straight relationships and their brain).

OTOH, one could argue with that that the survey is correct and that "real" bisexuality (as in: "would have true relationship - and not just sex - with any gender") is rarer among men. Hmmm :)