OAKLAND, Calif. -- An exclusive new KTVU field poll shows that for the first time ever, more California voters support allowing same-sex marriage than oppose it.

The results mark the first time in over three decades of Field Poll surveys that more California voters have approved of extending marriage to gay couples than have disapproved, said Field Poll director Mark DiCamillo. The survey of 1,052 registered voters was conducted over the phone.

"I would say this is a historic turning point or milestone," DiCamillo said. "We have speculated in the past there would be some time in the future when a majority would support same-sex marriage. Well, the lines have crossed."

The poll found that 51 percent of respondents backed legalizing same-sex marriage and 42 percent opposed it, DiCamillo said.

In 2006, when participants were asked, "Do you approve or disapprove of California allowing homosexuals to marry members of their own sex?" 44 percent said they approved and 50 percent objected. In 1977, the first year Field posted the question to voters, 28 percent approved and 59 percent were opposed.

The poll was conducted from May 17 to May 26 in the days after the California Supreme Court handed down its historic ruling legalizing same-sex marriage in the nation's most populous state. A smaller percentage of respondants-- 48 percent -- said they agreed with the court's decision and 46 percent disagreed.

DiCamillo said the jump in support for same-sex marriage indicates that voters were "influenced in some way by the judgment of the high court."

"I am left to surmise that had some impact on voters who might have been on the fence or marginally opposed," he said.

Voters were similarly divided on the subject of a proposed ballot initiative that would overturn the court's ruling by putting a gay marriage ban in the state constitution. Field asked respondents about it two ways -- once referencing the specific measure a group is seeking to get on the November ballot and once talking about a marriage amendment more generally.

Fifty-four percent opposed the amendment when presented with the issue generally, a figure that dropped to 51 percent when respondents were told they might have the chance to vote on a specific measure in November. Support for the amendment stood at 40 percent and 43 percent.

DiCamillo said the numbers could change once the amendment qualifies for the ballot, but the early results indicate "the concept itself is not widely embraced."

The Field Poll's finding conflicts with a Los Angeles Times/KTLA poll of 705 voters released last week that found 54 percent backed the proposed gay marriage ban and 35 percent opposed it. The Field survey had a margin of sampling error of plus or minus four percentage points on the general amendment question, and plus or minus five percentage points on the more specific question.

Andrew Pugno, legal adviser for the coalition of religious and social conservative groups sponsoring the measure, said the Times poll is more consistent with his group's internal polling.

"We could acknowledge there has been increasing acceptance of the idea of gay relationships over the last 10 or 20 years, but we think when it comes to marriage there is still a solid majority who want to see it reserved for a man and a woman, and that is all this initiative is about," Pugno said.