Shehan Welihinda, left, and Ryan Wilson react after participating in a marriage ceremony at City Hall in Baltimore, Tuesday, Jan. 1, 2013. Same-sex couples in Maryland are now legally permitted to marry under a new law that went into effect after midnight on Tuesday. Maryland is the first state south of the Mason-Dixon Line to approve same-sex marriage. (AP Photo/Patrick Semansky)
As the Supreme Court prepares to hear two cases concerning marriage equality for same-sex couples, a look at the legal battles and the controversies over gay marriage in the United States.