San Diego Mayor Jerry Sanders will testify Tuesday at the federal trial to decide the constitutionality of a gay marriage ban.

Sanders, a Republican, will testify in support of a gay and a lesbian couple, each of which has been denied the right to marry in California because of Proposition 8, the gay marriage ban approved by voters in 2008. The trial opened last week in San Francisco and will resume on Tuesday.

During a December 2007 press conference, Sanders announced he could no longer oppose gay marriage. He attributed his change of heart to the idea that “separate is not equal.”

With his wife by his side, an emotional Sanders said: “I have close family members and friends who are members of the gay and lesbian community. Those folks include my daughter, Lisa.”

“He's testifying essentially on his experience on the issue and why he believes marriage equality is important from a government perspective,” spokesman Darren Pudgil told The San Diego Union-Tribune.

Sanders is expected to testify at 8:30AM.