San Francisco’s equal marriage trial, now in its third week, has been marked by moving testimony about the pain denial of marriage has inflicted on same-sex couples and their families and the discrimination and abuse gays and lesbians continue to experience in their everyday lives.

In the first-ever trial in federal court on marriage equality, plaintiffs Kristin Perry and Sandy Stier of Berkeley and Paul Katami and Jeff Zarrillo of Burbank seek to overturn California’s Prop. 8 on grounds it violates the equal protection clause of the U.S. Constitution. The constitutional amendment passed by voters in 2008 defines marriage as between a man and a woman.

The plaintiffs rested their case Monday after introducing videos produced by Prop. 8 backers, claiming equal marriage would lead to pedophilia, polygamy, incest and bestiality. Attorneys for the two couples had earlier called as a hostile witness William Tam, director of the Traditional Family Coalition and one of five official proponents of the constitutional amendment. During the campaign, Tam wrote to supporters that “other states would fall into Satan’s hands” if equal marriage prevailed in California.

Defense attorneys opened their testimony by calling Claremont McKenna College political science professor Kenneth Miller, who sought to counter earlier testimony by Stanford University academic Gary Segura that gays and lesbians lack “meaningful” political power despite some backing in high places.

Miller claimed anti-gay discrimination is declining, and said gays and lesbians have powerful political, corporate, union and media allies. Under cross-examination, however, Miller acknowledged the military’s “don’t ask, don’t tell” policy, the federal law defining marriage as between a man and a woman, and the absence of openly gay elected officials in any California statewide office. He also acknowledged his testimony was partly based on information supplied by the defense attorneys.

A highlight of the trial’s second week was the account by San Diego’s Republican mayor, Jerry Sanders, of how his attitude toward equal marriage was transformed. As his daughter, a lesbian, and her wife watched from the gallery, Sanders said that though he and his wife wholeheartedly accepted their daughter’s relationship, he had remained an opponent of same-sex marriage.

Sanders said he initially planned to veto a City Council resolution supporting a court challenge to the state same-sex marriage ban, and his daughter said she would support his decision. But after a discussion with gay and lesbian friends, he reached a different conclusion.

“About 15 people spoke that night,” Sanders said. “But before the first one was finished, I shared their disappointment. It was then that I realized that all opposition to same-sex marriage, including my own opposition, was grounded in prejudice.” Sanders signed the resolution, and despite predictions his political career would be ruined, he was re-elected mayor the next year.

Among other highlights of the trial’s first two weeks:

• Gregory Herek, a psychology professor at the University of California-Davis, said the vast majority of self-identified gay men and lesbians believe they have little or no choice about their sexual identity, and that therapy to change sexual orientation has no scientific basis. He said “change therapies are especially harmful because they present the view that homosexuality is an illness or disorder,” leading people to think they are personally and morally at fault when the therapy fails. His testimony was supported by that of a gay man who described his pain at being subjected to the therapy by his family.

Witnesses have also testified that gay and lesbian parents are just as qualified as “straight” parents to raise children, and that procreation is not central to marriage.

• San Francisco’s chief economist, Edward Egan, told the court that legalizing same sex marriage would lower the city’s health and welfare costs. “Married individuals are healthier, on average, and behave in healthier ways than single individuals,” resulting in less absenteeism, more productivity, higher wages and payroll taxes, Egan told the court. He added that married people are more likely to have health insurance than are singles or domestic partners.

• Plaintiffs Perry, Stier, Katami and Zarrillo described in detail their feelings of discrimination over not being allowed to wed, and their outrage at the anti-gay slurs put forth by Prop. 8’s supporters.

Defense attorneys dropped four witnesses they originally planned to call, after the witnesses made statements during deposition harming the case for Prop. 8. The defense claimed the witnesses feared harassment if their testimony was broadcast during the trial, but initial plans to stream video of the proceedings were nixed by the U.S. Supreme Court before the trial began.

Chief U.S. District Court Judge Vaughn Walker’s decision in the non-jury trial is widely expected to be appealed, and ultimately to reach the U.S. Supreme Court.