Gary J. Gates is a scholar at the Williams Institute at the UCLA School of Law and co-author of "The Gay and Lesbian Atlas." This is from The Washington Post.

Back in the 1960s, pioneering gay activists found an obscure passage from a 1948 book by sex researcher Alfred Kinsey that read, "10 percent of the males are more or less exclusively homosexual . . . for at least three years between the ages of 16 and 55." They used that quote to claim that 10 percent of the population was gay, even though Kinsey's study wasn't designed to make a population-based estimate.

In those days, gay activists needed to prove the very existence of a gay community. One in 10 was big enough to "matter." But the percentage was not so large as to overly threaten a society still extremely uncomfortable with the idea of gay people. The fact that the 1-in-10 figure still gets bandied about is a testament to the brilliance of this political strategy.

Lots of Americans have no idea how many people are gay or lesbian. A 2002 Gallup poll suggested that one in six Americans had no estimate, and those who did put the figure at a whopping 20 percent.

As a demographer who studies the lesbian, gay, bisexual and transgender community, I've been asked how many LGBT people there are more often than I can count. Politics may still play a role in why the answer is important, but there certainly is no longer a need to prove that gay people exist. Today, quantifying the population is about documenting how LGBT people live their lives. How many marry? How often do they have children? How many are serving in the military? How often do they experience discrimination?

These facts matter because legislatures, courts and voters across the country are debating how LGBT people should live their lives. All parties deserve to be informed by fresh research, not a six-decade-old study.

We should be able to search the standard places where scholars and policy advocates go for information about the health and well-being of Americans -- all Americans. Places such as the Census Bureau's decennial count and American Community Survey, the premier sources of demographic data in this country. Or the National Health Interview Survey or Current Population Survey. But searching these sources for information about LGBT people would be largely futile. None ask questions about sexual orientation.

I recently averaged findings from across seven large surveys conducted since 2004 and found that nearly 9 million Americans (3.8 percent of adults) self-identify as LGBT. Nearly 26 million (11 percent) report some same-sex sexual attraction. But as a population scientist, I don't want to have to comb research for pertinent data to average.

I've attended dozens of meetings with representatives from federal statistical agencies to ask them why they aren't counting this population. They tell me that they worry about respondents refusing to answer such questions or terminating the survey. They also wonder exactly what questions to ask.

Should they count only those who explicitly identify themselves using terms such as "lesbian," "gay" or "bisexual"? Or should they measure sexual behavior? Or sexual attraction? The Ford Foundation recently funded a five-year study in which scholars considered these important questions and concluded that concerns about nonresponse or survey termination are unfounded. And not every survey must ask questions about every dimension of sexual orientation and gender identity. Rather, they should consider what dimensions make sense to measure, given the purpose of the survey.

The Institute of Medicine of the National Academies recently released a comprehensive analysis of the state of research on LGBT health and well-being. Recommendations from the report include LGBT inclusion across a wide range of federal surveys, coupled with increased support for federally funded LGBT research. Federal statistical agencies can and should heed this call. Such data could provide the building blocks for critical research to understand the lives of these Americans, who have too often been marginalized by researchers, as well as society at large.

I often hear LGBT advocates lament that it seems absurd that they don't have equal rights in this country, given how large their community is. As a demographer, I'm amazed at how close we are to equality, given how small the community is.

Both perspectives are valid, but both depend in part on an accurate assessment of the community -- however you define it. Assumptions about people are flimsy; numbers are solid. The reality of our political system is that you don't really count unless you are counted. So it's time to stop believing an old estimate and start making an accurate count.