It is always difficult to determine sexual minorities through surveys because of the complexities of self-identification, definitions, survey methodologies and stigmas. It is estimated by Harris Interactive that in the U.S. only 2% of self-identified lesbians and gays will respond to telephone surveys (compared to 3% of general population), but between 6%-7% will do so on Internet surveys. Confirming this finding, a Yahoo survey of its users found 7.1% of adults over age 18 identified as GLBT, totaling 18 million in the U.S.

Various studies have estimated that between 4% and 10% of populations are homosexual, meaning between 12 million and 30 million in the United States alone.

A 2002 study, "Sexual Behavior and Selected Health Measures," of 12,571 Americans aged 15-44 (by computer interviews conducted by the University of Michigan) for the National Center for Health Statistics found 6% of men and 11% of women had same-sex sexual experiences by age 44. Among men 18 to 44, 2% identified as bisexual and 4% as "something else" than heterosexual or bisexual. When looking at younger women, aged 18 to 29, 14% reported a sexual experience with a woman at least once.

Lesbians are estimated at over 6 million in the U.S. Data from Voter News Service and Zogby International consistently measure 4% to 5% of the American voting population as self-identified gay or lesbian. Studies by Kinsey in 1948 and Janus in 1993 have found bisexuals to represent between 22% to 37% of the population, though identifying them is quite difficult.

Increasingly, American gay marketing firms and major gay rights organizations are finding agreement that about 6%-7% of the overall population identifies as gay, with higher concentration in major cities.In late 2006, research analysis from Gary Gates and the Williams Institute on Sexual Orientation Law and Public Policy at the University of California, Los Angeles, concluded that 10 cities exceed 8% in concentrations of bisexuals, gays and lesbians, with San Francisco predictably topping the list at 15.4%, followed in order by Seattle (12.9%), Atlanta (12.8%), Minneapolis (12.5%), Boston (12.3%), Oakland, CA (12.1%), Sacramento (9.8%), Portland, OR (8.8%), Denver (8.2%), and Long Beach, CA( 8.1%).Surprisingly, New York, Los Angeles and Chicago didn't make the list.

Gates used data from the National Survey of Family Growth, a multipurpose survey sponsored by the U.S. Department of Health and Human Services, to conservatively estimate that 4.1% of the US identifies as gay, lesbian or bisexual, totaling 8.8 million people between the ages of 18-45. He then applied that data to the results of the American Community Survey, a periodic census update, to estimate the number of GLB people in cities, metropolitan areas and congressional districts. His formula assumed that the percentage of all same-sex coupled households in any area as provided by the census reflects the percentage of all gays, lesbians and bisexuals in that same area.

Still, marketing firms choose to go with the number who identify as gay as opposed to the actual population incidence, since those who do not think of themselves as gay will not be reached through traditional gay marketing.) The U.S. total population of gay- and lesbian-identified adults is expected to be roughly between14 million and 16 million.

In Britain, the government released figures in December 2005 showing that 6% of the British population is gay or lesbian, which translates into 3.6 million people. The Department of Trade based its estimates on the findings of various studies during the past 15 years. Among them are two studies conducted by the National Survey of Sexual Attitudes and Lifestyles (NATSAL), one in 1989-90 of 19,000 people and another in 1999-2001 of 11,000 people found detailed results about sexual experiences and same-sex couples. A small, indirect study conducted by Stormbreak in 2000 (a survey at the Gay Life & Style exhibition in July 2000, had 283 exhibition visitors complete a questionnaire, of whom two-thirds were gay men and one third lesbians) extrapolated about 7% of the British population to be gay. In late 2005, England enacted a civil partnerships law. The government estimates that 3.3% of gay men and lesbians over the age of 16 will be in registered civil partnerships, compared with around a third of the straight population who will be married.

In 2001, the census bureau in Canada, Statistics Canada, found 1.24 million lesbians and gays, equaling 8.1% of the population, though such questions are often thought to be underreported due to lingering fears and fluid identity issues. It also found 0.5% of couples (34,200) were same-sex pairings. A more recent report by StatsCan, the Canadian Community Health Survey, found only 1% of the population reported a gay identity -- which typically yields lower numbers than those reporting behavior, since many people do not identify as gay despite having same-gender sexual relations. (Quebec reported the highest percentage of gays, 2.3% of the population, followed by British Columbia at 1.9% and Ontario with 1.5%.) Preliminary results of a survey by Ottawa-based Vanier Institute of the Family found 2.8% of Canadians identified as gay or bisexual.

Media and Marketing Europe (2002) reported that "at least 6% of Sweden's 8.8 million population are gay." A June 2002 report from The Netherlands, the first country in the world to recognize gay marriage, found 50,000 gay couples there, a 25% increase from five years earlier. In Australia, over 19,500 same-sex couples reported themselves to the 2001 census, equaling 1.5% of all couples there.

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