See a list of the policies of different Christian denominations on homosexuality at ReligiousTolerance.org, which also maintains a list called “Homosexuality and religion: Policies of non-Judeo-Christian religions.”

FindLaw.com offers a history of legal cases (scroll toward bottom of page) on same-sex marriage.

The Constitutional Law Prof blog highlights legal cases involving same-sex marriage, the Defense of Marriage Act and other matters dealing with sexual orientation.

Lamba Legal lists countries and states that allow gay couples to marry or that recognize or provide protections for same-sex relationships through other means. Note that the publication was last updated in September 2011, so it doesn’t reflect recent changes.

Gallup conducts a “values and beliefs” survey each May. Read about the 2013 results, which found a record 59 percent of Americans saying that gay and lesbian relations are morally acceptable. A Gallup/USA Today poll released in December 2012 found that religious beliefs were the reason most often cited as the basis for opposing same-sex marriage.

The Pew Research Center released survey results in June 2013 indicating that LGBT adults are, on the whole, significantly less religious than the general public.

A poll conducted for CNN in June 2013 found that 55 percent of Americans support same-sex marriage and 60 percent say the federal government ought to recognize those unions that are performed in states allowing them.

Read a May 5, 2013, Stateline article that predicts “Momentum in the states to allow gay marriage may be about to stall.”