SAN FRANCISCO — Sexual orientation can be fluid, but the vast majority of people have identities that are consistently heterosexual, gay or bisexual throughout most of their lives, a social psychologist testified Friday in a trial challenging California's gay marriage ban.
Lawyers for two same-sex couples suing to overturn the voter-enacted ban called University of California, Davis researcher Gregory Herek as their final expert witness to bolster their argument that sexual orientation cannot be easily changed.
The point is central to the plaintiffs' effort to show that gays deserve the same judicial protection as racial and ethnic minorities.
The trial, which ended its ninth day, is the first in a federal court to consider whether state bans on gay marriages are unconstitutional.
"Most heterosexual men and women, if they were asked the question and thought about it, would report similarly that they don't feel they made a choice to be heterosexual," Herek said.
The plaintiffs are expected to finish presenting evidence on Monday, with lawyers for Proposition 8 sponsors then beginning their case. Chief U.S. Judge Vaughn Walker, who is hearing the case without a jury, said he would delay closing arguments for two weeks after the defense rests so he can review the testimony.
On Friday, Herek said he recently conducted a survey asking people if they decided to be gay, lesbian or bisexual. Eighty-eight percent of the gay men who responded said they had no choice at all about their sexual orientation. The figure was 68 percent for lesbians.
Herek also said it's clear that gay men and lesbians are looked down upon and even regarded with disgust because of long-standing social stigmas.
"If two men were to walk down the street holding hands in many places, that would elicit a great deal of negative reaction, and that is an example of the stigma that everyone knows lesbians and gay men experience because they are gay," he said.
Proposition 8 was by definition an extension of embedded social stigmas, he contended.
Howard Nielson Jr., a lawyer for Proposition 8 sponsors, cross-examined Herek about whether sexual orientation is as fixed as Herek implied.
Nielson cited some of Herek's writings stating that some people who regularly engage in sex with people of the same gender do not necessarily identify as gay, while others may have same-sex attractions they never act on.
He also quoted the work of Sigmund Freud and pioneering sex researcher Alfred Kinsey to suggest that sexual orientation can and sometimes does change over a person's life.
Herek acknowledged that was true, but added: "Most people display consistency in their attractions and behaviors. We do see some examples where some people express attraction but do not have the sexual behavior."
Nielson also drew on pretrial testimony from plaintiff Sandy Stier, who is seeking the right to marry her female partner of 10 years. Stier said she had been married to a man for 12 years before she fell in love with a woman.
Nielson read from a transcript in which Stier said she had not always been interested in women and at one time was physically attracted to her ex-husband.
"At that point in her life, Miss Stier would not have been gay, correct?" Nielson asked.
Herek said many men and women who identify as gay have had opposite-sex partners.
Under Nielson's questioning, Herek readily acknowledged that scientists do not know if people are born gay or straight, become that way as a result of their early experiences, or some combination of circumstances.