There is little reliable evidence about what percentage of the U.S. population is in reality gay or lesbian, due to few representative surveys asking about sexual orientation, complexities surrounding the groups and definitions involved, and the probability that some gay and lesbian individuals may not choose to identify themselves as such. Demographer Gary Gates last month released a review of population-based surveys on the topic, estimating that 3.5% of adults in the United States identify as lesbian, gay, or bisexual, with bisexuals making up a slight majority of that figure. Gates also disputes the well-circulated statistic that “10% of the males are more or less exclusively homosexual.”

Americans’ current collective estimate — which is substantially higher than Gates suggests — is likely driven more by perceptions and exposure than by scientific measurement or reality. Gallup previously found that a majority of Americans personally know someone who is gay or lesbian, though Gallup did not ask Americans how many gay or lesbian individuals they know, or whether they know more individuals now than they did before. Additionally, Americans tend to have difficulty estimating percentages of population groups whose numbers are more widely known. Gallup a decade ago found Americans estimating much larger U.S. black and Hispanic populations than what the U.S. Census Bureau reported for those groups.