In Pasadena, the pastor of the 4,000-member All Saints Church spoke out against Proposition 8, calling the religious community's support of it "embarrassing."
In Orange County, police officials and protest organizers estimated that about 250 to 300 gay-rights advocates fanned out along sidewalks leading to Saddleback Church in Lake Forest.
The protesters were angered by the megachurch's support of Proposition 8, a constitutional amendment approved by voters Tuesday that bans same-sex marriages and overturns the state Supreme Court decision in May legalizing such unions.
Human Rights Campaign volunteer Ed Todeschini accused the church of helping propagate what he called misinformation about the Supreme Court ruling, including that gay marriage would have to be taught to kindergartners.
A message for comment left at the church's main office, which was closed Sunday, was not immediately returned.
"They told such obvious lies, they used their lies to deceive the public," Todeschini said of the church, which gained national attention in August when its pastor, Rick Warren, brought Obama and McCain together to discuss their religious faith. The two candidates embraced during what was otherwise an often-contentious presidential campaign.
Todeschini said Sunday's rally was peaceful, with demonstrators waving placards with slogans including "Equality for all" and "Shame on you."
In Oakland, where the highway patrol rerouted traffic, protest organizers said they hoped to tone down the anger that has characterized some previous protests.
"Our intent is not to disturb churchgoers," organizer Tim DeBenedictis said in a statement. "Our goal is to mend fences and build bridges so that all Californians can achieve marriage equality under the law."
A spokesman for the Oakland temple said Mormons were being unfairly singled out, noting that the ban was backed by a variety of religious groups.
Rallies have been taking place since Proposition 8's passage with 52 percent of the vote.
Not all churches favor Proposition 8. In Pasadena, the All Saints Church announced that while it could legally no longer marry same-sex couples, it would continue blessings of gay civil unions.
"It's very unfortunate and embarrassing that the (Christian religion) is in large part responsible for this act of bigotry," the Rev. Ed Bacon told The Associated Press following his Sunday sermon.
Bacon heads the 4,000-member All Saints Church.
The protest at the state Capitol was boisterous but peaceful as speakers led the crowd in noisy anti-Proposition 8 chants. Protesters waved rainbow flags and No on 8 signs as police watched from the sidelines.
Jovannah Radtke of Sacramento told The Sacramento Bee on Sunday that same-sex marriage supporters are more energized now than in the days leading up to the election.
"There is a lot more enthusiasm and passion," she said.
Speaking on CNN's "Late Edition" Sunday, Gov. Arnold Schwarzenegger expressed disappointment at Proposition 8's passage.
"It is unfortunate," Schwarzenegger told CNN correspondent John King. "But it is not the end because I think this will go back into the courts. ... It's the same as in the 1948 case when blacks and whites were not allowed to marry, this falls into the same category."
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