The Defense of Marriage Act, or DOMA, is the short title of a federal law of the United States passed on September 21, 1996 as Public Law No. 104-199, 110 Stat. 2419. The law has two effects: 1. * No state (or other political subdivision within the United States) need treat a relationship between persons of the same sex as a marriage, even if the relationship is considered a marriage in another state. 2. * The Federal Government may not treat same-sex relationships as marriages for any purpose, even if concluded or recognized by one of the states.