The landmark DOMA ruling awarded equal federal rights to opposite-sex couples on a 5-4 ruling stating that the federal government must recognize their marriage status. Justices found the DOMA in violation of the equal protection statute in the US Constitution, BBC reports.

Prop 8

In a separate decision regarding proposition 8, the state of California has again legalized gay marriage by ridding the state of the ban.  
A total of twelve US states and the District of Columbia allow gay marriage, while 30 others still do not.