By Lawrence Hurley

WASHINGTON (Reuters) - The Supreme Court on Tuesday agreed to decide whether gender inequity in U.S. immigration law over granting citizenship to children born abroad to unwed American-citizen parents - favoring mothers over fathers - violates the U.S. Constitution.

The case involves a convicted felon from the Dominican Republic named Luis Morales-Santana, who was denied U.S. citizenship even though his father was a citizen. It marks the second time the high court has taken up the issue. In 2011, it split 4-4 in a similar case, leaving the matter unresolved.

In July 2015, the 2nd U.S. Circuit Court of Appeals in New York sided with Morales-Santana and struck down the law at issue, saying it applied "impermissible stereotyping" in imposing a tougher burden on fathers. The U.S. Justice Department asked the high court to take the case.

The law requires unwed fathers who are U.S. citizens to spend at least five years living in the United States - a 2012 amendment reduced it from 10 years - before they can confer citizenship to a child born abroad, out of wedlock and to a partner who is not a U.S. citizen.

For unwed U.S. mothers in the same situation, the requirement is only one year.

Morales-Santana, 54, was convicted of several offenses in 1995, including two counts of robbery and four counts of attempted murder. The U.S. government has sought to deport him since 2000.

Morales-Santana's deceased father was an American citizen, while his mother was not. His father failed to meet the law's requirements by 20 days, according to Morales-Santana. He has lived legally in the United States since 1975.

His court-appointed lawyers argued that the law's disparate treatment of mothers and fathers violated the U.S. Constitution's equal protection principle.

In the earlier case, Justice Elena Kagan recused herself, likely due to her previous job as a senior Justice Department lawyer before she was appointed to the court in 2010.

The court will hear oral arguments and issue a ruling in its next term, which begins in October and ends in June 2017.

(Editing by Will Dunham)