By Moni Basu, CNN
(CNN) - Measuring the nation's gay population has always been tricky. Those who identify as lesbian, gay, bisexual or transgender are still subject to social stigma, and many are not comfortable answering questions about their identity.
But in the largest survey of its kind conducted by Gallup, 3.4% of all Americans identified themselves as part of the LGBT community.
Gallup interviewed 120,000 Americans and found that the highest percentages of LGBT identification occurred among non-white, younger and less educated Americans.
Demographer Gary Gates said the survey sheds light on the diversity and complexity of the LGBT community.
"They offer an unprecedented resource for informing LGBT-related debates like those regarding marriage, parenting and workplace discrimination with much-needed facts rather than stereotype or anecdote," said Gates, a scholar with the UCLA School of Law's Williams Institute, which researches sexual orientation and gender identity issues.
The survey differs from the 2010 census, which for the first time measured sexual orientation. But the census counted same-sex partners and same-sex spouses - 516,396 households.
Of note in the latest Gallup survey, released Thursday, is the fact that non-whites are more likely to identify themselves as LGBT than whites, which challenges common belief that large numbers of the community are white, male and wealthy.
The Gallup poll showed that 4.6% of African-Americans identify as LGBT along with 4% of Latinos and 4.3% of Asian-Americans. Only 3.2% of white Americans say they are LGBT.
More women - 3.6% - identified as LGBT than men - 3.3%. That means 53% of the LGBT community are women.
And, perhaps not surprisingly, younger adults between the ages of 18 and 29 were more than three times as likely as seniors 65 and older to identify as LGBT - 6.4% of younger Americans said they were LGBT versus 1.9% of older people.
The new survey showed LGBT identification is highest among Americans with the lowest levels of education. Of those with a high school education or less, 3.5% identify as LGBT compared with 2.8% of those with a college degree and 3.2% of those with post-graduate education. LGBT identification is highest among those with some college education but not a college degree, at 4.0%.
How will America's LGBT population affect the presidential election?
Gallup found that 44% of LGBT Americans identify as Democratic; 43% as independent; and only 13% as Republican. That compares to 32% of non-LGBT Americans who identify as Democratic, 39% as independent, and 30% as Republican. The respective numbers in the non-LGBT community are 32% Democratic, 39% independent and 30% Republican.
"Given the strong Democratic tilt of the LGBT population, it is not surprising that registered voter preferences of LGBT Americans tilt strongly - but not monolithically - toward Barack Obama," the survey said. "Specifically, 71% of LGBT Americans who are registered voters support Obama, while 22% support Mitt Romney."