gay marriage or same-sex marriage is a kind of marriage happens between two persons of the same sex, sound strange but hold true in western countries like USA and in rest of the world for example in some European countries. Although same sex marriages are not officially recognized by federal law at all places/region. But now Gay Marriage Is Legal in U.S Capital as Published in The New York Times (U.S) on March 3, 2010. In the picture you can see Jonathan Howard, left, and Gregory Jones, right, who applied for a marriage license on Wednesday in Washington.
same-sex marriage license laws in the U.S varies from one state to another. For legal details and more information on this you are advised to read DOMA in detail.
DOMA is the Defense of Marriage Act, it is a legislation that was signed into law by President Clinton in 1996 . As per this act marriage is the legal union of a man and a woman. DOMA allows states to not recognize same-sex marriage licenses issued by other states.