With the impression that gay culture can not survive long term with the model of stable unions, homosexual activists began in the late 1980s to fight for a legally recognized union (domestic partnership) , a registered concubinage ( civil union, registered concubinage), or a homosexual marriage ( same-sex marriage ). Berkeley in 1984 is the first U.S. city where gay couples can register. In the federal capital of Washington, domestic partnerships become legal in 1992, and they give homosexual couples rights similar to married couples. Later follow California (1999), Maine (2004), Washington (2006) and Oregon (2008). The first state where gay couples can enter into a civil union is Vermont. Follow Connecticut (2005), New Jersey (2006) and New Hampshire (2008) .

The vanguard fighters for gay marriage can note a first success, when the Supreme Court of the State of Hawaii in the case of Baehr v.. Lewin decides that the refusal to issue marriage licenses to homosexual couples is under the Constitution of the State of Hawaii a sex discrimination cases. In 1996, President Clinton enacted, however, theDefense of Marriage Act  (in) (Law for the Defense of Marriage), the two main points are:

• The provisions regarding unions homo-or heterosexual taken in a district of the United States beyond the principle of mutual recognition laid down by the Constitution
• Marriage is defined as a union between a man and a woman.

Even Hawaii adopted a constitutional amendment in 1998 ( n ^o  2) that prevents same-sex marriages in that state.

In spring 2004, the San Francisco Mayor-elect Gavin Newsom raises international attention when he gives the instruction to the registrar of the county to issue marriage licenses to gay couples also. From 12 February 4000 couples get married, until, March 11, 2004, the California Supreme Court decides that such marriages are void . The first state where same-sex marriages can be made ​​legally is May 17, 2004, Massachusetts, where the Supreme Court decided November 18, 2003 in the case Goodridge v.. Department of Public Health that the legal benefits enjoyed by heterosexual married couples, can not be denied to same-sex couples.