SAN FRANCISCO — At Most Holy Redeemer Catholic Church in the Castro, this city’s largest gay district, about 20 of the faithful gathered for 8 a.m. Mass recently, clustering in the middle pews. Led by a visiting priest from nearby Oakland, the parishioners joined in celebrating the 30th anniversary of a gay couple.

The celebration was not out of place in San Francisco, at least not in those parishes that have somehow bridged the colossal gap between their gay members’ lives and church doctrine.

But the appointment of a new leader of the archdiocese here — Bishop Salvatore Cordileone, 56, a rising conservative who led the fight against same-sex marriage in California — has many gay and lesbian Roman Catholics worried about the fate of these sanctuaries.

At a cafe where some of the parishioners met after Mass, many said they would take ‘‘a wait-and-see’’ attitude toward Cordileone, who has led the Oakland Diocese for the past three years and is scheduled to be installed as archbishop here Thursday, the feast of St. Francis, San Francisco’s patron saint. Some expressed hope that in getting to know his followers here, Cordileone would come to see things their way.

Others were more defiant, saying nothing would shake their faith.

asking for patience

“In a sense, I am glad that the Church is sending the top guy that they have — the top ­anti-gay — because it means that we, as a community of Catholics, have done something good to deserve attention,’’ said George Woyames, 68, who added that he was raised as a Roman Catholic but became committed to the religion only after joining Most Holy Redeemer in 1987.

Cordileone was one of the leading proponents of Proposition 8, which banned same-sex marriage in November 2008 by defining marriage in California as between only a man and a woman. The proposition, which voters endorsed after hard-fought campaigns on both sides, overturned a decision just months earlier by the California Supreme Court that legalized same-sex marriage. But legal challenges to the ban have been working their way through higher courts since then.

Cordileone is also the chairman of the US Conference of Catholic Bishops’ subcommittee for the defense of marriage, whose mandate is ‘‘promoting and defending the authentic teaching of the church regarding the nature of marriage as a covenant between one man and one woman.’’

In The Voice, the newspaper of the Oakland Diocese, Cordileone said it was ‘‘too early to say’’ what he would focus on as the archbishop of San Francisco.

‘‘I need to get a better lay of the land,’’ he said. Asked what is the one thing people in San Francisco should know about him, Cordileone, who has also been active against the death penalty and in favor of an immigration overhaul, said he was ‘‘not a single-issue person.’’

But experts said the appointment of a figure so strongly associated with opposition to same-sex marriage as archbishop of San Francisco, the heart of the gay rights movement, inevitably carries a message from the Vatican. In keeping with the growing conservatism of the Catholic Church in the United States, Cordileone’s installation comes as the Supreme Court prepares to weigh in on the issue of same-sex marriage.

Supporters of Proposition 8 said they were heartened by the selection of Cordileone.

‘‘It’s great for the church, and it’s great for San Francisco that he’ll be archbishop,’’ said Brian Brown, the president of the National Organization for Marriage, one of the many groups that campaigned for Proposition 8. ‘‘He’s a real leader on this issue.’’

Cordileone was busy preparing for his installation and was unavailable for an interview, said Mike Brown, a spokesman for the Oakland Diocese. Last month, the bishop was arrested in San Diego on a drunken-driving charge; he apologized in a statement.

The bishop’s record on marriage stands in contrast to those of predecessors who have tried to accommodate gay residents of San Francisco.

Some of those archbishops regularly visited parishes like Most Holy Redeemer or appointed priests sympathetic to parishes with many gay members.

For nearly two decades, until 1995, the San Francisco Archdiocese was led by Archbishop John R. Quinn, a standard-bearer of liberal Catholicism.

He made strategic appointments, naming, for example, a priest who helped bring about Most Holy Redeemer’s transformation from an aging parish to one made up mostly of gay men.

In 1997, Archbishop William Levada brokered a deal that allowed the church to comply with a city regulation requiring that benefits be paid to the unmarried partners of people doing business with the city.