U.S. adults, on average, estimate that 25% of Americans are gay or lesbian. More specifically, over half of Americans (52%) estimate that at least one in five Americans are gay or lesbian, including 35% who estimate that more than one in four are. Thirty percent put the figure at less than 15%.
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.
... Americans perceive that there is a large U.S. gay population -- one far larger than is likely reality.
Here is a video report provided by Gallup: