Sociologist here (well Sociology degree anyway)... I agree with the abstract from Tiger Tim's second paper.
10% is an inflated number based on Kinsey's research which had some methodological problems and has been pretty well debunked.
Sunsequent surveys that have gone out have reported anywhere from 1%-8% in US males depending on how you classify homosexual behavior (whether by attraction, behavior or identity). And with any survey there's people who won't report their sexual orientation out of fear, shame etc so all numbers are questionable.
The US census puts it at about 2% in most major metro areas (Higher in NY and SF) but it's limited to gay couples living together, which I think excludes most of us... (based on numbers from this site we're 76% single)
Homosexuality varies (or seems to vary) by ethnicity, region and culture, making a true number or percentage difficult to achieve. So while data on this site can tell us something about the population, it doesn't give us any indication how many of us there really are.
What we do know is there seem to be consistently fewer lesbians than gay men.
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