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University of Southern Maine campus police said 35 people from both sides of the Question 1 referendum campaigns carried signs and chanted outside the Abromson Community Education Center on the Portland campus on Wednesday.

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Brian Souchet, left, a representative of the Yes on 1 Stand for Marriage Maine campaign, shakes hands with Mary Bonauto, who spoke for the No on 1 Protect Maine Equality campaign after the close of their debate Wednesday at the University of Southern Maine.

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An estimated 500 people formed the audience that gathered to listen to speakers during an hourlong debate on the same-sex marriage referendum Wednesday at the University of Southern Maine in Portland. The forum was sponsored by WMTW-TV, USM and MaineToday Media.

PORTLAND — Maine's referendum on same-sex marriage, which has generated a wave of television commercials and fierce public debate, took center stage Wednesday night in a debate between representatives from both campaigns.

Brian Souchet of Brunswick, representing opponents of same-sex marriage, said marriage is a unique arrangement between a man and a woman that should be protected.

Mary Bonauto of Portland, representing supporters of the new law allowing same-sex marriage, said the issue is about fairness and equality.

About 500 people watched the debate in the Abromson Community Education Center on the University of Southern Maine's Portland campus. Those who couldn't get seats in the Hannaford Hall auditorium were able to watch a video broadcast in another room of the building.

Campus police estimated that 35 people from both campaigns, carrying signs and chanting slogans, stood outside the Abromson center. No disturbances were reported, despite the strong emotions that have run throughout the campaign.

A bill to allow same-sex marriage was approved by the Legislature and signed by Gov. John Baldacci in May. Question 1 on Tuesday's statewide ballot asks voters whether they want to repeal the law.

Souchet, who spoke for Yes on 1, Stand for Marriage Maine, is married and said he works on the campaign full time. He filled in Wednesday for Marc Mutty of Stand for Marriage Maine, who could not participate because of illness.

Bonauto, speaking for No on 1, Protect Maine Equality, said she has been in a relationship with another woman for more than 20 years. They have two children.

A panel of journalists posed questions to both, and the debate's moderator, Shannon Moss of WMTW-TV, asked questions submitted from the audience and by e-mail from viewers at home.

"All people in Maine should be treated equally under our laws," Bonauto said in her opening remarks. "Why would any of us in Maine want to stand in the way of that happiness?"

Souchet called same-sex marriage "a radical redefinition of marriage."

Moss noted a recent poll showing that about 52 percent of voters would uphold the law, with another 6 percent undecided.

Despite any polls, Bonauto said her campaign is taking nothing for granted. "We expect this vote to be won by a razor-thin margin."

The debaters disagreed on whether same-sex marriage would be taught in public schools. Education Commissioner Susan Gendron has said it would not become part of any school's curriculum because of the law.

"If this bill were to become law," Souchet argued, "we have no reason to believe we won't be discussing homosexual marriage in our schools."

But Bonauto, whose two children attend Portland schools, said that public schools always allow students to opt out of discussions they don't feel comfortable hearing.

"Schools need to make sure that all their students feel safe," she said. "That reality is not going to change."

Souchet called same-sex marriage "a relatively new social experiment. Marriage will lose its meaning when you gut it."

He said he believes it's important for a child to be raised by a mother and father.

"A mother and father do matter. They each play a unique role in the rearing of our children," he said.

Bonauto said that if same-sex marriage is prohibited, gay and lesbian couples will suffer financially. "We all matter, every single one of us, and we deserve equal protection under Maine laws," she said.

"I'm fairly certain you will see an outbreak of happiness and an awful lot of weddings" if the repeal effort is rejected, she said.

Julia Casuse Gagnon of Topsham wore a bright yellow Yes on 1 campaign button as she stood outside the lecture hall alongside No on 1 supporters.

Gagnon said there is no substitute for the "unique" relationship between a man and a woman who give birth to a...