Of course bi guys exist. The thing that makes me skeptical though is the method of research. People can have all manner of physical reactions to visual stimuli based on their penchant for certain 'taboos' or merely because they possess an 'unusual' factor. Anyone can be aroused by same sex porn and not necessarily want to be sexually intimate with the same sex. Fantasy accounts for so much sexual arousal it's almost ridiculous. Surely a 'question and answer' kind of thing is far more reliable. Anything can turn us on, suddenly and without warning - but that doesn't necessarily colour our sexuality to the same extent that the whole tactile, chemical, intellectual stimulation that is provided by an interesting, sexually attractive person - who's very good at what they do. To me the best measure of bisexuality - is someone being open and honest about their their desire and willingness to fuck either sex. It's not that complicated really.
Rose Cooper. read a girls own bi story here: www.insiderose.com