On Dec. 7, 2012, the U.S. Supreme Court agreed to review a number of federal appeals court decisions on same sex marriage: one striking down part of the federal Defense of Marriage Act (DOMA), which defines marriage as a union between a man and a woman, and another invalidating California's Proposition 8, a ballot measure passed in 2008 that amended the state's constitution to ban gay marriage.

A Pew Forum research package examines various aspects of the same-sex marriage debate:

• An overview of the same-sex marriage debate
• An in-depth legal backgrounder on the two cases the Supreme Court has just agreed to review
• An overview of where 16 religious groups stand on gay marriage
• A map that shows same-sex marriage policies in each of the 50 states
• A graphics slideshow that shows how public opinion toward same-sex marriage has changed in Pew Research Center polling since 2001