When California's Supreme Court struck down the state's ban on same-sex marriage May 15, the justices cited only one of the 45 amicus curiae briefs submitted to support their decision: the one APA filed as lead amicus, with other mental health organizations signing on.

The court's 4-3 decision held that restricting marriage to opposite-sex couples violated the state's constitution.

The court's opinion specifically cited the amicus curiae brief that APA filed along with the California Psychological Association, the American Psychiatric Association and the National Association of Social Workers and its California chapter. "The fact that the psychological literature we cited in the brief did get used by the court is a great accomplishment," says Clinton W. Anderson, PhD, director of APA's Lesbian, Gay, Bisexual and Transgender Concerns Office.

Drawing on psychological evidence

Same-sex couples who register as domestic partners in California already have virtually all the state-level rights, benefits and obligations that married couples do, thanks to a series of domestic partnership laws passed by the Legislature. (Federal benefits, such as Social Security and Medicare, are still unavailable to same-sex couples.) Basically, same-sex couples in California could be married in all but name. That linguistic difference was the crux of the case, says APA General Counsel Nathalie Gilfoyle, JD. "It really was about the use of the term 'marriage,'" she says, noting that the law explicitly restricted that term to opposite-sex couples.

APA's brief offered the court plenty of rigorous psychological evidence about why that one word makes such a big difference.

Research regarding the impact of stigma was key, explains Gilfoyle, noting that APA's brief laid out the scientific evidence on the stigma of having different names depending on whether the relationship was between people of the same or opposite sex. The brief also highlighted the evidence on such issues as the nature of same-sex relationships and the fitness of lesbian and gay parents.

Even though California's same-sex couples already had the same rights as married couples under state law, the court concluded, denying them the right to describe themselves as married implied that their unions are less valuable.

Noting the importance of marriage to both individuals and society, the court decided that the reasons for protecting marriage apply equally to both opposite-sex and same-sex couples. Denying same-sex couples the right to use the term "marriage" means they can't exercise the right to marry enshrined in the state's constitution, the court concluded.

In addition, the court decided that denying same-sex couples the right to marriage violated the state constitution's guarantee of equal protection under the law. Limiting the use of the word "marriage" to opposite-sex couples, the court concluded, represented discrimination on the basis of sexual orientation rather than just a disparate burden on lesbian and gay individuals.

One of the most important outcomes of the case, says Gilfoyle, is that it establishes that in California sexual orientation is subject to what's called "strict judicial scrutiny." When strict scrutiny applies, the state has to convince the court that discriminating against a certain category of people is the only way to accomplish a compelling government objective.

The court cited the brief's explanation of the nature of sexual orientation in its elevation of sexual orientation into a "suspect class" requiring strict scrutiny by the courts.

"From here on out, California law is going to treat sexual orientation the same way it treats gender, race, religion and similar classifications," explains Gregory M. Herek, PhD, a psychology professor at the University of California, Davis, who helped draft the brief. "That's a very big deal."

Next steps

The three dissenting judges noted that they support the idea of same-sex unions but believe the decision should be made by voters.

Californians will get a chance to make their opinion known in November.

An initiative aimed at amending the state constitution to prohibit same-sex marriage will be on the ballot. Conservative groups and attorneys general of several states had urged the court to stay its ruling until California voters had their say, but the court refused.

Herek remains optimistic.

"One of the claims that often gets made is that these decisions reflect the will of a small, elite number of judges," he says. "In this case, the justices are very much in sync with the state Legislature and with what the governor has said."

The state Legislature has twice passed legislation granting same-sex couples the right to marry, only to face vetoes by a governor who said he believed that state law made it unconstitutional for him to sign such legislation, says Herek. The court's decision has eliminated that objection, since the justices declared that such laws were themselves unconstitutional.

Meanwhile, Herek predicts a rush to get married by Californians and nonresidents alike.

California law, he points out, doesn't require people getting married in the state to be residents. New York recently announced that it would recognize same-sex marriages, which are now legal in Massachusetts, several countries and some Canadian provinces as well as California.

"I expect we'll have a large number of people from out of state coming here to get married," says Herek.

Rebecca A. Clay is a writer in Washington, D.C.