The U.S. Supreme Court says it will rule on two same-sex marriage cases next year challenging state and federal laws that limit the definition of marriage to the union of a man and a woman.

The High Court said Friday it will review a federal appeals court ruling that struck down Proposition 8 — the California ban on gay marriage passed by referendum in 2008. The appeals court earlier this year ruled that voters could not override same sex marriage rights granted in a state Supreme Court ruling.

Voters have endorsed gay marriage in nine states and the District of Columbia. But 31 states have amended their constitutions to prohibit same-sex marriage.

The Supreme Court said it will also decide whether Congress can deprive legally married gay couples of federal benefits available to heterosexual couples.

Currently, a provision in the 1996 Defense of Marriage Act restricts health and pension benefits to heterosexual couples, who also benefit from favorable tax policy not available to gay couples.

The cases are expected to be argued in March, 2013, with rulings expected in June.

Section 3 of the law limits the definition to the union of a man and a woman and extends that definition to hundreds of federal laws and programs. The challenge comes from an 83-year-old woman who was hit with a $363,000 federal estate tax bill after her partner of more than 40 years died in 2009. Had she been married to a man, her tax bill would have been zero.

The court's decision to hear the cases coincides with evidence of rapidly changing attitudes in America about gay marriage. Recent national polling shows the majority of Americans support such unions, and the push for equal protection gained strength in November elections, when the number of states authorizing gay marriage grew to nine.