LAKE WORTH — About 300 people showed up outside city hall Saturday to register their opposition to Florida's passage of Amendment 2, which effectively bans gay marriage in the state.

The local protest, organized by the group Justice First, was one of three gay rights protests in South Florida and part of a national effort to protest similar gay-marriage bans that passed this month.

Hundreds came out to protest in front of Miami Beach City Hall, and more than 1,000 people attended a rally in Fort Lauderdale.

Amendment 2 passed with 61.9 percent support from Florida voters on Nov. 4. California and Arizona also passed bans on gay marriage, and Arkansas passed a measure prohibiting gays from adopting children.

In Lake Worth, protesters stood along Dixie Highway as drivers at times honked their horns in support. Protesters waved signs that said "Let My Moms Get Married," "Shame On You," "Honk To Undo Prop 2" and "Marriage Is A Human Right."

Protesters said even more people would have attended the rally, but many local gay rights activists were cycling to Key West as part of a fund-raiser for AIDS research.

Though some states have allowed gay couples to form a civil union, couples said marriage is crucial to validate their relationship. Even those with a civil union have had problems seeing their partner in the hospital because they are not a legal spouse or because it is not recognized where they live.

West Palm Beach resident Mary Nugent and her partner, Lisa Brennan, attended the Lake Worth rally with Nugent's brother Irvine. Nugent and Brennan have a civil union from Northern Ireland and would like to get married in Florida.

"We're hoping for a change," Mary Nugent said. "We're in love and we'd like to have a law that protects that love. We feel vulnerable if we're not married."

Brennan hopes people who voted for Amendment 2 would reconsider their opposition to gay marriage.

"There's nothing to be afraid of. We shouldn't be second-class citizens," Brennan said.

The nationwide protest movement began to gather momentum after the Nov. 4 elections. Last week, more than 8,000 people attended a rally in New York City.

On Saturday, thousands protested in Boston. Crowds also gathered near public buildings in New York, San Francisco and Chicago to vent their frustrations, celebrate gay relationships and renew calls for change.

The protests had particular meaning in Miami Beach and Fort Lauderdale - two cities known for having large gay populations. More than 300 couples are registered as domestic partners in Miami Beach, which has some of the broadest domestic partnership laws in the country.

"South Florida can be the example," said Babak Movahedi, chairman of Miami Beach's gay business development committee. "Dare I say it, if marriage rights were up to cities and not the state, I think we would have gay marriage here."

In Fort Lauderdale, mayoral candidate Dean Trantalis, who is openly gay, spoke of the alienation of the gay community.

"This is a slap in the face for everyone seeking equal rights, especially because (the ban) came at a time for change in our country," said Trantalis, speaking of Sen. Barack Obama's election.

Planning for the nationwide protests was started by a Seattle blogger, Amy Balliett, days after the California vote, which took away gay marriage rights that had been granted by the state's high court.

The idea rapidly spread online and Join the Impact predicted that Saturday's protests would involve tens of thousands of people in hundreds of communities.

Massachusetts and Connecticut, which began same-sex weddings last week, are now the only states that allow gay marriage.

Protests following the vote on Proposition 8 in California, which defined marriage as between a man and a woman, have sometimes been angry and even violent, but the Lake Worth rally was upbeat. Protesters waved rainbow flags, held up signs and stood with their children.

One protester said a man who drove by and apparently opposed the rally parked his car at a nearby drugstore, where he bought poster board and held a one-man counter rally across the street.

Jay Blotcher, who helped organize a similar rally in New York last week, was married in California when it was legal.

The gay rights activist credits religious organization including churches with helping pass the marriage bans.

"Segregation doesn't work," he said. "We would never think of telling black and Latino couples they don't have the right to marry."