Gay couples waiting to hear Wednesday if New Jersey becomes the second U.S. state to allow same-sex marriage said the state Supreme Court's decision would make it one of the happiest or saddest days of their lives.

The New Jersey Supreme Court was poised to release the highly anticipated decision later Wednesday in a case brought by seven gay couples who say the state constitution allows them to marry, said Winnie Comfort, a spokeswoman for the state judiciary.

"If it's a yes, it will be one of the happiest days, if it's a no, it will be a huge disappointment," said Saundra Heath-Toby, a plaintiff in the case who would like to marry Alicia Toby-Heath, the woman she already calls her wife.

New Jersey is one of only five states with neither a law nor a state constitutional amendment blocking same-sex marriage. As a result, the state is more likely than others to allow gays to wed, said advocacy groups on both sides.

Only Massachusetts — by virtue of a 2003 ruling from that state's top court — allows gay marriages.

Proponents and opponents from across the country are watching the case closely.

"New Jersey is a stepping stone," said Matt Daniels, president of the Virginia-based Alliance for Marriage, a group pushing for an amendment to the federal Constitution to outlaw same-sex marriage. "It's not about New Jersey."

From a practical standpoint, the Massachusetts court decision made little impact nationally because the state has a law barring out-of-state couples from wedding there if their marriages would not be recognized in their home states.

New Jersey has no such law.

People on both sides of the issue expect a victory for same-sex unions would make New Jersey a destination for gay couples from around the country who want to get married. Some of those couples could return home and sue to have their marriages recognized.

Daniels said gay-rights advocates are already looking ahead to such lawsuits. "Their game, of course, is they figure all they need to do is execute this maneuver in a half-dozen states and they'll have the momentum," he said.

David S. Buckel, the Lambda Legal lawyer who argued on behalf of the seven New Jersey couples, said he expects some couples would travel to the New Jersey to get married if his suit is successful. But, he said, "it won't be tidal."

Buckel said that there have been relatively few such lawsuits filed in the U.S. by couples who went to Canada to exchange vows.

And, he said, while many same-sex couples would prefer to be married, they are getting more legal protections for their relationships. Several states, including New Jersey, offer domestic partnerships or civil unions with some of the benefits of marriage. A growing number of employers are treating same-sex couples the same way they treat married couples.

Cases similar to New Jersey's are pending in California, Connecticut, Iowa and Maryland.

Conservatives watching the cases believe the best chance for gay marriage to be allowed would be in New Jersey, where the state Supreme Court has a history of extending civil rights protections.

Gay marriage supporters have had a two-year losing streak, striking out in state courts in New York and Washington state and in ballot boxes in 15 states where constitutions have been amended to ban same-sex unions.