The U.S. Census Bureau is making an unprecedented effort to include same-sex couples in next year's national population count, but counting the number of individuals who identify as gay, lesbian or transgender could be next.

Census representatives told community leaders in San Francisco on Thursday that categories could be added in future editions of the bureau's annual American Community Survey.

They say it was too late to include questions about sexual orientation or gender expression in the 2010 tally.

The survey is designed to give state and local governments a snapshot of how their populations are changing. It is much more detailed than the 10-question census form that will be mailed to every household in March.