By Will Lester
The Associated Press

WASHINGTON - More than half of Americans favor a law barring gay marriage and specifying wedlock be between a man and a woman, an Associated Press poll found.

The survey also found presidential candidates could face a backlash if they support gay marriage or civil unions, which provide gay couples the legal rights and benefits of marriage.

The poll, conducted for the AP by ICR-International Communications Research, found 52 percent favor a law banning gay marriages, while 41 percent oppose it.

About four in 10 - 41 percent - support allowing civil unions, roughly the same level found in an AP poll three years ago. But 53 percent now say they oppose civil unions, up from 46 percent in the earlier survey.

The increase came largely from people who previously were undecided, the polls suggested.

Close to half those surveyed said they would be less likely to support a presidential candidate who backs civil unions (44 percent) or gay marriage (49 percent), while only around 10 percent said they would be more likely.

"I don't think it's a great idea. The whole idea of marriage is bringing up children," said Jim Martin, a 64-year-old engineer from Alexandria, Va. "If somebody was promoting it, I would vote against them."

The issue poses a challenge for the Democratic presidential candidates in the 2004 election. The six leading candidates say they oppose gay marriage but are sharply critical of efforts to legally ban it.

Four of the six - former Vermont Gov. Howard Dean, Missouri Rep. Dick Gephardt, Florida Sen. Bob Graham and Massachusetts Sen. John Kerry - support civil unions.

North Carolina Sen. John Edwards and Connecticut Sen. Joe Lieberman say they favor benefits for gay partners, but say states should decide on civil unions.

President Bush has said he supports efforts to legally ban gay marriage, but encourages tolerance of gays and lesbians.

Gay rights have gotten increased attention since June, when the Supreme Court threw out a Texas law prohibiting gay sex, saying such a ban violates constitutionally guaranteed privacy rights. The decision mobilized Christian conservatives, who warned it could lead to legalization of gay marriage.

The poll found 54 percent favor a constitutional amendment that marriage only be between a man and a woman, while 42 percent oppose it.