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 Bishop Cordileone, who has led the Oakland Diocese for the past three years and is scheduled to be installed as archbishop here on Thursday, the feast of St. Francis, San Francisco’s patron saint. Some expressed hope that in getting to know his followers here, Bishop Cordileone would come to see things their way.

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

“In a sense, I am glad that the church is sending the top guy that they have — the top antigay — 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.