The nine justices of the U.S. Supreme Court are widely expected to decide in a private meeting on Friday to enter the legal fray raging over same-sex marriage.
An announcement to take a case could come as early as Friday afternoon or Monday morning.
Thirty-one of the 50 states have passed constitutional amendments banning gay marriage while Washington, D.C., and nine other states have legalized it, three of them on Election Day, November 6.
At issue is the 1996 Defense of Marriage Act, or DOMA, passed by Congress, which only recognizes marriages between a man and a woman. Gay men and lesbians have specifically challenged a part of the law that prevents them from receiving federal benefits that heterosexual couples receive.
The high court is considering requests to review five cases that challenge the law as a violation of the equal protection provisions of the U.S. Constitution.
Most courts to address the issue, including federal appeals courts in Boston and New York, have found the law's contested provision unconstitutional.
The Supreme Court is expected to take at least one of the challenges, as the court typically reviews lower-court decisions that invalidate a federal law.
Even in states where same-sex marriage is legal, the couples do not qualify for a host of federal benefits because of DOMA.
If the court accepts one of the cases, the oral arguments will likely take place in early 2013, with a ruling expected by the end of the court term in June.
If the court invalidates the law, states could still be free to legalize or deny same-sex marriages on their own terms.
Friday's scheduled court conference is one of the Supreme Court's regular weekly sessions at which it considers what new cases to add to the calendar.
The meetings, attended only by the justices, are held in a small conference room adjacent to the chambers of Chief Justice John Roberts.
The justices vote in order of seniority, and while it takes five of the nine for a majority decision in a dispute, it takes only four votes to add a case to the agenda and schedule oral arguments.
The court is also considering whether to review a challenge to California's ban on same-sex marriage, known as Proposition 8, which voters narrowly approved in 2008. The California case, Hollingsworth v. Perry, had sought to establish a constitutional right to marry for gays and lesbians.
The 9th Circuit in February found the gay marriage ban unconstitutional, but it ruled narrowly in a way that only affected California and not the rest of the country, finding that the state could not take away the right to same-sex marriage after previously allowing it. No other state to legalize gay marriage has later banned it.
If the Supreme Court later takes the case, it could follow the 9th Circuit's decision and also rule narrowly, requiring same-sex marriage only in California but not the rest of the country. Or it could recognize a right to marriage equality.
If the justices decline to take the case, the 9th Circuit's opinion would stand, and same-sex marriage would resume in California. That would significantly boost the number of same-sex couples able to marry, given the state's large size.
The Supreme Court is also considering an appeal from the state of Arizona, asking the court to revive a state version of DOMA. The Arizona law, which the 9th Circuit invalidated, eliminated domestic partner healthcare benefits for gay and lesbian state employees. Same-sex couples in Arizona cannot marry, under that state's constitutional ban passed in 2008.
(Reporting by Terry Baynes in New York; Editing by Howard Goller and Cynthia Osterman)