The Supreme Court has agreed to review two cases dealing with same-sex marriage, and the outcomes could have significant consequences for employers. At issue in Windsor v. United States is whether the Defense of Marriage Act (DOMA) deprives legally married same-sex couples of equal protection under the law and thus is unconstitutional.

Section 3 of DOMA provides that:

In determining the meaning of any Act of Congress, or of any ruling, regulation, or interpretation of the various administrative bureaus and agencies of the United States, the word "marriage" means only a legal union between one man and one woman as husband and wife, and the word "spouse" refers only to a person of the opposite sex who is a husband or a wife.

Under DOMA, same-sex spouses are not recognized as legally married for purposes of federal law, which affects health and pension benefit rights as well as the federal tax treatment of benefits provided to a same-sex spouse. If the Supreme Court rules that DOMA is unconstitutional, the federal government would have to recognize all same-sex marriages legally entered into under state law.

The other case, Hollingsworth v. Perry, challenges California's Proposition 8, the constitutional amendment approved by voters in 2008 that banned same-sex marriages in California. If the Supreme Court decides to invalidate California's same-sex marriage ban, it could confine the impact of its holding to California or it could extend it on broader U.S. constitutional grounds, thereby invalidating same-sex marriage bans in more than 30 other states.

The Supreme Court will likely hear the cases in March 2013 and rule by late June.