SAN FRANCISCO (AP) – By a relatively narrow margin, Californians remain opposed to marriage for gays and lesbians but are more solidly against a constitutional amendment banning the weddings, a new poll showed.

The nonpartisan Field Poll showed 50 percent of Californians opposed marriage for gays and lesbians, compared to 44 percent who supported them.

But when it comes to a constitutional amendment banning such unions, which President Bush advocated, the survey of registered voters showed a solid majority were opposed, 55 percent to 40 percent. The poll was conducted before Bush’s announcement.

“It’s a fairly big deal to change the U.S. Constitution,” said Mark DiCamillo, director of the Field Poll. “There are true conservatives that don’t want to tamper with the Constitution. Some voters may be opposed to same-sex marriages, but aren’t willing to change the U.S. Constitution.”

The support for marriage equality has remained relatively constant over the past six months, despite the heavy publicity generated by San Francisco Mayor Gavin Newsom’s decision to hand out more than 3,400 marriage licenses to gay and lesbian couples in the past several weeks.

But the long-term trend in California clearly is moving in favor of marriage for gays and lesbians. Approval has risen 16 percentage points since the Field Poll first asked the question in 1977, while opposition has dropped from 59 percent to 50 percent.

Approval rates also vary depending on the age of respondents, with voters between the ages of 18 and 29 showing 58 percent support and those 65 and older showing 26 percent support – another sign of the growing acceptance.

“The majority of Californians in the future will likely approve of same-sex marriage if the current trends hold,” DiCamillo said.

Like age, religion is also an indicator of support. Of people who attend a religious service weekly, 80 percent are opposed to the marriages, compared to 27 percent of people who never attend.

“It shows the cultural divide in America,” DiCamillo said. “That’s what the Bush administration sees when it sees the advantage of this.”

The region with the strongest support is the San Francisco Bay area, where 57 percent of people approve of marriage for gays and lesbians. It’s the only region in the state with majority support.

The Bay Area is also the only region to support Newsom’s decision to allow gay and lesbian couples to obtain marriage licenses, with 55 percent approving. Overall, 55 percent of Californians oppose the mayor’s actions.

But when it comes to a constitutional amendment, residents in Los Angeles, Orange and San Diego counties also are opposed.

The poll, conducted Feb. 18 through 22, was drawn from interviews with 958 registered California voters. The poll had a sampling error of plus or minus 3.3 percentage points.