“We heard through the Prop. 8 debate great concern from certain clergy that their freedom of religion could be infringed upon and their tax-exempt status revoked,” said the bill’s author, Sen. Mark Leno, D-San Francisco. “We want to clarify that by putting the constitutional guarantee of the First Amendment, freedom of religion, into statute.”

The bill would apply to any religious objection to performing a marriage, not just between same-sex couples, and states that no clergy member would be required to solemnize a marriage that conflicts with his or her faith. The bill states that refusing to do so “shall not affect the tax-exempt status of any entity.”

The threat of churches losing their tax-exempt status for refusing to perform same-sex marriage ceremonies was prominent in the campaign in favor of Prop. 8, the measure that reinstated the ban on those marriages in California.

Backers of the legislation, including the state’s largest gay rights organization, said the bill also will clarify differences between civil and religious marriage. The proposal would place the word “civil” in front of references to marriage.

“There is confusion among many people whether a marriage license is a civil document or a religious document. It’s a civil document, and this is putting that in the code so there is no confusion,” said Geoff Kors, executive director of Equality California.

Several religious organizations support the measure, including the California Southern Baptist Convention, which supported Prop. 8. Terry Barone, spokesman for the convention, called it “good legislation.”

“That certainly would seem to add protections for a clergy member who, for whatever reason, might be hesitant to perform a marriage ceremony,” he said.

The proposal also has the backing of California Church Impact, the advocacy arm of the California Council of Churches, which represents about 6,000 congregations and 6.5 million Californians, according to the organization. That group opposed Prop. 8, even though its members were divided on the issue.

Rick Schlosser, executive director of the advocacy group, called the proposal a “perfect bill” because of its recognition of religious freedom. He acknowledged, however, that religious freedom includes the freedom to treat gay and lesbian couples differently than heterosexuals.

“We very strongly oppose discrimination in any form anywhere, so that is an issue and concern for me. However, because some churches would refuse to perform same-sex marriages doesn’t deny a couple the right of getting married,” Schlosser said.

E-mail Wyatt Buchanan at wbuchanan@sfchronicle.com.

This article appeared on page C – 1 of the San Francisco Chronicle