The AP's Lisa Leff reports that officials at the  2010 Census are struggling to work out how to count married and unmarried same-sex couples when spousal rights for gay couples differ so widely from state to state:

"The U.S. Census Bureau is making an unprecedented effort to include same-sex couples in next year's national population count, but legally married gay couples won't show up as such in the official once-a-decade tally, bureau representatives said Thursday. Statistical problems related to the development of the 2010 census form and the evolving legal state of same-sex relationships led Census officials to conclude that trying to include married gay couples in the overall snapshot of household marital status could yield an inaccurate number, said Gary Gates, a University of California, Los Angeles demographer who has been advising the bureau on gay issues. Instead, same-sex married couples will be added into the category for unmarried partners, just as they were for the 2000 census. But in a marked policy departure, the agency plans to make the data on same-sex couples who described themselves as married available on a state-by-state basis. 'The Bureau has decided to give us the information, but be a little cautious,' Gates said. The decision to develop separate sets of numbers was a compromise position that was 'less about politics and more about accurate data,' he said."

They add: "...it's become clearer that a wildly inflated number could be produced if the number of heads of household who said they lived with another adult of the same sex, and described that person as a husband or wife, were only counted. Some couples in civil unions or domestic partnerships, or who live as spouses in states where gay couples have no spousal rights, have tended in past surveys to identify themselves as husbands or wives anyway, according to Gates."

Also: "Although the census has not attempted to count individuals who identify as gay, lesbian or transgender, they could be included in the next count or even future editions of the annual American Community Survey, Olsen said. The survey, which is much more detailed than the 10-question census form that will be mailed to every household in March, is designed to give state and local governments a snapshot of how their populations are changing. Olsen said gay leaders need to keep advocating if they want to be recognized."

Census bureau says 2020 count could include gays [ap]