The next US census, to be carried out next year, will not ask about sexual orientation or recognise gay marriages, civil unions and domestic partnerships.
If two men or two women who live together list themselves as husband and husband, or wife and wife, they will be counted as unmarried partners.
The federal Defence of Marriage Act, signed in 1996 by President Bill Clinton, does not recognise gay unions sanctioned by states.
US Census Bureau spokeswoman Cynthia Endo said: “This is all about the numbers. This not about lifestyle or anything else.”
Sharon Raphael, a sociologist who lives with her partner Mina Meyer, told the Press-Telegram: “Certain numbers of us are not out, and when they hide us under these general descriptions … it just makes us more invisible.”
“We should be treated the same. First of all, it’s just not good science to leave us out for some dumb political reason.”
Gary Gates, a demographer at the UCLA School of Law, said that federal law limits census questions to topics for which there is funding, such as income’s influence on poverty funding.
There is not a federal funding category for the lesbian, gay, bisexual and transgendered, or LGBT, communities..
He added that the situation is a “classic catch-22″ because it is hard to properly assess needs of a group that has not been counted.
Tracy Clark-Flory of Salon.com argued that including such information “could inject some potent political power into the lesbian, gay and transgender community”.
She added that the results of the census are used by the federal government to make spending decisions on areas such as healthcare.
However, census questions cannot be changed without an act of Congress. As Congress must approve questions no later than two years in advance of the survey, it is too late to change the 2010 count.
The next UK national census will be held on 27th March 2011. For the first time the marital status question will include a civil partnership option, but there will not be a question on sexual orientation.