Bans on gay marriage in three staunchly conservative Southern states were to get a hearing in a federal appeals court Friday — the latest legal battle over an issue expected to be settled by the nation's highest court.

A three-judge panel of the 5th U.S. Circuit Court of Appeals was scheduled to hear arguments from state attorneys from Texas, Louisiana and Mississippi — all of which passed bans on same-sex marriages — and from the lawyers arguing against the bans.

The cases represent what could be among the last argued in federal court before the U.S. Supreme Court takes up the issue. The high court on Friday was eyeing the possibility of putting gay marriage on its calendar for this term.

Gay marriage is now legal in 36 states and Washington, D.C., as bans on gay and lesbian marriages have been struck down across the nation.

The appellate court in New Orleans took the highly unusual step of consolidating appeals from the three Southern states into one session, which is expected to last about three hours Friday.