PORTLAND (AP) - Most Oregonians oppose same-sex marriages, according to a statewide poll taken after Multnomah County's surprise decision to allow such weddings.

The survey of 400 voters, conducted for The Oregonian, found that 54 percent do not think same-sex marriages should be legal.

Thirty-five percent of those surveyed said the weddings should be legal and 11 percent were unsure.

The poll found big differences of opinion based on age and gender.

Among voters younger than 35, 53 percent said gay couples should be able to legally marry; 25 percent of voters age 55 and older said that should be the case.

"Twenty years from now, this could be a moot point," said Tim Hibbitts, the Portland pollster who conducted the survey.

More than 60 percent of men said they were opposed to gay marriage compared with 48 percent of women.

Multnomah County's decision sent the issue to the top of the political agenda, with nearly three-quarters of voters saying it is an important issue that the state should resolve now.

Opponents of same-sex marriage said the survey results show the public is with them in their attempt to qualify a proposed ballot measure that would amend the Oregon Constitution to allow marriages only between one man and one woman.

"That's the reason we feel so strongly the debate needs to be taken to Oregonians," said Tim Nashif of the newly formed Defense of Marriage Coalition, "and that's why we're so aggrieved that the Multnomah County commissioners didn't allow us to do that."

Gay-rights activists said they face a tough fight if the measure reaches the November ballot, but they think attitudes are starting to change.

"This is a new issue for most people," said Roey Thorpe, executive director of Basic Rights Oregon. "It's something they're just starting to learn about, and our job would be to educate them about what marriage rights are and how marriage for everyone strengthens families and helps children."

When asked how society should deal with same-sex relationships, about a third of Oregon voters said they want to preserve traditional marriage and would oppose civil unions for gays. Another third support gay marriage, and 29 percent said they back civil unions that would legally recognize same-sex relationships.

That means there could be a majority for some form of civil union.

The poll showed Oregon Republicans are much more unified in their opposition to gay marriage - 77 percent oppose it and 14 percent support it - than are Democrats, who narrowly support it, 47 percent to 41 percent opposed.