Demographic Picture Emerges on Same-Sex Couples

Washington — A few salient facts are known about the Americans whose lives might be changed by a Supreme Court ruling on same-sex marriage expected this summer.

About one in five gay and lesbian couples are raising children that are under age 18. Same-sex couples are less likely than traditional married couples to have health insurance covering them both. One in 10 men with a male partner or spouse is a military veteran. As many as 6 million Americans, roughly 2 percent of the population, have a parent who is lesbian, gay, bisexual or transgender.

These nuggets of demographic insight into same-sex couples were contained in an amicus brief filed last week in connection with two cases before the Supreme Court on the constitutionality of California’s gay marriage ban and the Defense of Marriage Act.

A decade ago, such precise statistics were impossible to come by. But as gays become more visible in politics, challenging laws that stigmatize their relationships, demographic research into lesbians and gays is emerging from the shadows.

“There is quite a bit about the LGBT population we don’t know,” said Gary Gates, one of the most prominent of only a few demographers focusing on gay statistics, who drew on census data for the demographic brief filed in the Supreme Court.

However the Supreme Court rules in the gay marriage cases, demographic knowledge about gays and lesbians is poised to expand further.

The National Health Interview Survey of 35,000 Americans started in January to ask respondents to identify their sexual orientation, alongside questions about health insurance, obesity, vaccinations and smoking. The goal is to identify disparities in health needs that could be addressed, officials say. Last year, the government began asking employees their sexual orientation in the annual workforce survey.

A Gallup poll released earlier this month found that 3.5 percent of American adults identify themselves as lesbian, gay, bisexual or transgender.

Some opponents of gay marriage also say more research should be done into gay demographics, in part to correct common misperceptions on the size of the gay community. In surveys, Gallup has found that Americans believe, on average, that 25 percent of the population is gay, several times higher than any research estimate.

The decennial census now provides hard numbers on the number of same-sex couples, or at least the growing number who are willing to identify themselves as such. The 2010 census counted 646,000 couples living with same-sex partners, including 130,000 same-sex married couples.