The court said it will decide two questions: Whether states must allows same-sex couples to marry and whether states must recognize same-sex marriages that take place out-of-state. The court will hear an extended two and a half hours of oral arguments in April.
The plaintiffs include two nurses from Michigan, April DeBoer and Jayne Rowse, and Louisville.
"We are now that much closer to being fully recognized as a family, and we are thrilled," DeBoer said.
"We are excited obviously for our clients and for the many thousands of couples like them in Michigan, but we are also excited for the entire nation," added Dana Nessel, a lawyer for the Michigan plaintiffs.
Attorney General Eric Holder said President Barack Obama`s administration will file court papers supporting the plaintiffs and seeking to legalize gay marriage nationwide. Obama in 2012 became the first sitting president to support gay marriage.
"It is time for our nation to take another critical step forward to ensure the fundamental equality of all Americans - no matter who they are, where they come from, or whom they love," Holder said.
Most of the states that are defending state bans had, like the gay rights advocates, urged the high court to take up the issue in order to resolve the legal uncertainty.
Supporters of gay rights have touted same-sex marriage as one of the leading American civil rights issues of this era. Gay right groups quickly urged the justices to issue a nationwide ruling endorsing the legality of gay marriage.
"It’s time for America to no longer be a house divided when it comes to the freedom to marry," said Brian Silva, executive director of the group Marriage Equality USA.
Chad Griffin, president the Human Rights Campaign, called the pending high court ruling the "moment of truth."
LEGAL SEA CHANGE
There has already been a legal sea change, thanks in large part to the Supreme Court’s prompting. It began in earnest in June 2013 when the court struck down a federal law that restricted, for the purpose of federal benefits, the definition of marriage to heterosexual couples. Obama`s Justice Department refused to defend the law.
Judges around the country later seized on the language in the high court decision, written by swing vote Justice Anthony Kennedy, to strike down a series of state bans.
At the time of the 2013 ruling, only 12 states had authorized gay marriage. It is now legal in 36 of the 50 states.
Michigan Attorney General Bill Schuette, a Republican defending the state`s ban, welcomed the court`s announcement, saying the state and nation "will be well served" by a definitive ruling.
Although the gathering momentum toward gay marriage has been prompted largely by the courts, opinion polls show that support among Americans has been rising in recent years. But many conservative Christians remain steadfastly opposed.
Brian Brown, president of the National Organization for Marriage, which opposes same-sex marriage, said he is hopeful the court will rule "in favor of voters` right to define marriage as the union of one man and one woman."
The court’s expected June ruling would come as the field of candidates for the 2016 presidential election takes shape, and the issue could factor into the race. Democrats are generally in favor of gay marriage while Republicans are divided on the issue.
The primary legal issue is whether the state bans and the refusal to recognize out-of-state marriages violates the U.S. Constitution`s guarantee of equal protection under the law.
As recently as October, the court decided not to intervene in the gay marriage issue when seven cases from five states were pending. That decision not to hear the disputes had huge legal implications because it meant that gay marriage went ahead in five states and paved the way for it to begin in several others.
A Nov. 6 decision by the Cincinnati-based 6th U.S. Circuit Court of Appeals to uphold marriage restrictions in four states increased pressure on the Supreme Court to take up the matter. It was the first of the nation`s regional federal appeals courts to uphold gay marriage prohibitions after the wave of other rulings declaring the bans unconstitutional.
The Supreme Court is divided on gay rights, with Kennedy likely to be the key vote. It is not known how he would rule on gay marriage but he has a history of backing gay rights.