A vigorous supporter of California's same-sex marriage ban was named Friday as the next Roman Catholic archbishop of San Francisco.

The Vatican announced that Pope Benedict XVI selected the Rev. Salvatore Cordileone, the presiding bishop of Oakland, to replace Archbishop George Niederauer in October. Niederauer, 76, is retiring.

As an auxiliary bishop in San Diego four years ago, Cordileone, 56, was instrumental in devising an initiative to strip same-sex couples of the right to wed in California and then raising Catholic dollars to qualify it for the ballot.

He also was part of a statewide network of clergy that promoted the measure, known as Proposition 8. Campaign finance records show he personally gave at least $6,000 to back the voter-approved ban.

Since last year, Cordileone has been chairman of the U.S. Conference of Catholic Bishops' Subcommittee for the Promotion and Defense of Marriage.

In an interview with the National Catholic Register last year, Cordileone said that same-sex marriage is "a very serious social experiment that will have dire consequences." Opposing it is "not a matter of religion," he said.

At a news conference at St. Mary's Cathedral in San Francisco Friday, he said he thought the Roman Catholic Church had come a long way in addressing the issue of clergy sex abuse and reiterated his position on gay marriages.

"Marriage can only come about through the embrace of a man and a woman coming together," he said. "I don't see how that is discriminatory against anyone."

Gay rights groups criticized the Pope's choice of Cordileone to lead the San Francisco Archdiocese, which serves more than 400,000 Catholics in the city and neighboring Marin and San Mateo counties. As archbishop, he also will oversee the bishops in Honolulu, Las Vegas, Oakland, Reno, Sacramento, Salt Lake City, San Jose, Santa Rosa, and Stockton.

"While LGBT Catholics and their allies have worked relentlessly to create welcoming environments, the appointment of Bishop Cordileone sends a chilling message that, in the eyes of the hierarchy, same-sex relationships are not worthy of equal dignity and respect," Human Rights Campaign President Chad Griffin said.

A Field Poll released in February found that 51 percent of the Catholic respondents support same-sex marriages.