Updated

The leading Democratic presidential candidates support gay couples having the same legal rights as husbands and wives, but stop short of saying they have a right to marry.

Most of the White House hopefuls attending a presidential forum hosted Tuesday by the Human Rights Campaign (search) - a leading gay advocacy group - expressed their support for gay civil unions.

Only three candidates - Al Sharpton, Carol Moseley Braun and Rep. Dennis Kucinich of Ohio - said federal law should approve same-sex marriages.

The comments of the top candidates did not go over well with some in the crowd. The audience hissed when Sens. Joe Lieberman of Connecticut and John Kerry of Massachusetts said marriage is a right reserved in America for men and women.

"Marriage has a special status in our culture, our society, our history," Lieberman said.

Despite the differences over gay marriage, the Democratic presidential candidates agree with most of the policy positions of the Human Rights Campaign. They expressed support for anti-discrimination laws, hate crimes legislation, increased funding for HIV/AIDS (search) research and treatment, and federal domestic partnership benefits.

But the issue of gay marriage is sure to dog the candidates - both the Democrats and Republican President Bush - in next year's election. Elizabeth Birch, executive director of the Human Rights Campaign, said the group also would invite Bush and other Republicans to future forums.

Several congressional Republicans, led by Senate Majority Leader Bill Frist, R-Tenn., have called for a constitutional amendment banning gay marriages. Bush has said "marriage is between a man and a woman," but he has sidestepped the constitutional amendment issue.

Vermont is the only state that has a civil-unions law (search) giving gay couples the same legal rights as married couples - a law signed by former Gov. Howard Dean, one of the presidential contenders to address the forum. Dean said civil unions, in the absence of marriage, give gays legal rights, such as health benefits, inheritance, child custody and hospital visitation.

Under tough questioning from moderator Sam Donaldson, Dean said extending marriage to gays is problematic "because marriage has a long, long history as a religious institution."

But Sharpton said simply granting civil unions is a form of discrimination against gays, "like saying we'll give blacks or whites or Latinos the rights to shack up, but not marry."

Same-sex marriages are legal in Belgium and the Netherlands, and Canada's Liberal government announced last month that it would enact similar legislation soon. Dean and Rep. Dick Gephardt of Missouri were asked if they would recognize those marriages if the couples immigrated to the United States. Although Dean did not answer the question directly during an interview last month on NBC's "Meet the Press," he said he had come to the conclusion that they should be recognized.

So did Gephardt. "I think the federal government should conform its laws as quickly as we can to recognize whatever relationship - civil relationship, civil union, gay marriage - whatever is accepted and put into law in states or foreign countries," he said.

Gephardt told the audience about how he and his wife had embraced their daughter, Chrissy, when she announced a year and a half ago that she was leaving her husband because she was a lesbian. He drew applause from the audience when he said he and his wife had joined PFLAG, which stands for Parents, Families and Friends of Lesbians and Gays (search).

Appearing with Gephardt at a news conference following the forum, Chrissy Gephardt gave her father credit for favoring other rights for gay couples even though she disagrees with his position on marriage.

"I've talked to him about it all the time," she said. "I'm definitely a proponent of gay marriages."

Two of the nine presidential candidates, Sens. Bob Graham of Florida and John Edwards of North Carolina, did not appear at the forum.