I don't think we'll ever know, but the Gallup poll from 2002 was surprising. When asked in a poll, Americans said 21% of men are gay
and 22% of women are lesbians.
"In his 1948 book, Sexual Behavior in the Human Male, Alfred Kinsey shocked the world by announcing that 10% of the male population is gay. A 1993 Janus Report estimated that nine percent of men and five percent of women had more than "occasional" homosexual relationships. The 2000 U.S. Census Bureau found that homosexual couples constitute less than 1% of American households. The Family Research Report says "around 2-3% of men, and 2% of women, are homosexual or bisexual." The National Gay and Lesbian Task Force estimates three to eight percent of both sexes. So who's right -- what percentage of the population is homosexual?
It may be that no one will ever know for sure. To some people, homosexuality is a matter of perception and definition. Furthermore, many people have trouble admitting their homosexuality to themselves, much less to a researcher. But when Gallup asked Americans for their best estimate of the American gay and lesbian population, the results made all the figures mentioned above look conservative.
Every Fifth Person -- at Least
In August 2002*, Gallup asked Americans, in an open-ended format, to estimate the percentage of American men and the percentage of American women who are homosexual. The average estimates were that 21% of men are gay and 22% of women are lesbians. In fact, roughly a quarter of the public thinks more than 25% of men and 25% of women are homosexual. It should be pointed out, too, that many Americans (at least one in six) could not give an estimate.
Male respondents tend to give lower estimates of both the male and female homosexual population than female respondents do. The average estimates among male respondents are that 16% of men and 21% of women are homosexual. Among female respondents, the average estimates are that 26% of men and 23% of women are homosexual. Somewhat interestingly, both sexes believe there are more homosexuals in the opposite sex than in their own sex." http://www.gallup.com/poll/6961/what-percentage-population-gay.aspx