Tens of thousands of same-sex couples are expected to marry legally in California by 2010, if a constitutional ban on gay marriage doesn’t pass at the polls in November.

But no matter what the voters decide, the official government count of the number of married same-sex couples in California is not in doubt. It will be zero.

The U.S. Census Bureau, reacting to the federal Defense of Marriage Act and other mandates, plans to edit the 2010 census responses of same-sex couples who marry legally in California, Massachusetts or any other state. They will be reported as “unmarried partners,” rather than married spouses, in census tabulations – a policy that will likely draw the ire of gay rights groups.

The Census Bureau followed the same procedure for the 2000 census, and it does not plan to change in 2010 even though courts in Massachusetts and now California have ruled gay men and lesbians can marry lawfully.

“This has been a question we’ve been looking at for quite a long time,” said Martin O’Connell, chief of the Census Bureau’s Fertility and Family Statistics Branch. “It’s not something the bureau could arbitrarily or casually decide to change on a whim, because our data is used by virtually every federal agency.”

The Census Bureau is not falsifying people’s responses, O’Connell said, because the bureau will retain people’s original census responses.

“We’re not destroying data; we are keeping that data,” O’Connell said. “We are just showing the data published in a way that is consistent with the way every other agency publishes their data.”

The Census Bureau does not ask about sexual orientation, but it does ask people to describe their relationships to others in their household. If a respondent refers to a person of the same gender as their “husband/wife” on the 2010 census form, the Census Bureau will automatically assign them to the “unmarried partner” category. Legally married same-sex couples will be indistinguishable in census data from those who chose “unmarried partner” to describe their relationship.

Researcher’s view

Critics say the census plan will mask the records of legal, same-sex, married couples and therefore degrade the quality of the government’s demographic data.

“I just think it’s bad form for the census to change a legal response to an incorrect response,” said Gary Gates of the Williams Institute, a think tank at the University of California-Los Angeles law school that studies gay-related public policy issues. “That goes against everything the census stands for.”

Gates, a prominent demographer who was consulted by Census Bureau officials about counting legally married same-sex couples, said one result is that the census will undercount marriages in states with gay marriage. And because the bureau defines a “family” as two or more people related by birth, adoption or marriage, it also will remove many same-sex married couples from being counted as families.

“It’s a systematic hiding not only of married gay couples, but gay couples as families, which I would argue is a fundamentally political decision,” Gates said.

One recently married couple called the policy “frustrating.”

“It’s just another layer of the hurdles we have to jump, as far as our relationship being recognized,” said Jim Winstead of Hollister, who recently married his partner, Rodney Naccarato-Winstead. The couple have an 18-month-old son.

Gay rights groups, learning of the policy this week, were also critical.

“To have the federal government disappear your marriage I’m sure will be painful and upsetting,” said Shannon Minter, legal director for the National Center for Lesbian Rights. “It really is something out of Orwell. It’s shameful.”

A spokeswoman for ProtectMarriage.com, campaigning in favor of the constitutional ban, declined to discuss the census issue in detail, but said it illuminates how the legalization of gay marriage potentially could dictate policy changes on government.

“One of our campaign cornerstones will be the fact that if the initiative doesn’t pass that public schools will be forced to teach the difference between gay marriage and traditional marriage,” said Jennifer Kerns.

Bureau’s reasoning

A census technical note that explains the bureau’s rationale on counting same-sex partners for the 2000 census notes that the 1996 Defense of Marriage Act “instructs all federal agencies only to recognize opposite-sex marriages for the purposes of enacting any agency programs.”

O’Connell said the Census Bureau has been unable to find any federal agency that collects data on same-sex married couples. Changing the policy before the 2010 census also would be a huge and difficult logistical issue.

“The last thing anyone wants is to use the 2010 census as a trial run,” O’Connell said.

Gates said, however, that the limitations on access to people’s original responses will make it very difficult for private researchers to analyze raw data and back out the number of same-sex spouses in California or other states.

“It’s an official closet,” Gates said, “that the government has built.”