The U.S. Supreme Court case that will decide whether states can ban gay marriage marks another milestone in the history of the American gay rights movement.
Here is a look at some key events.
- The Mattachine Society, considered the first national U.S. gay rights organization, is founded in Los Angeles.
The U.S. Supreme Court, in the case One, Inc. v. Olesen, backs the free-speech rights of a gay magazine after U.S. postal officials and the FBI labeled it obscene and prohibited its mail distribution. It is seen as the first gay rights case before the Supreme Court.
Illinois becomes the first state to decriminalize sodomy.
Police raids at the Stonewall Inn, a popular gay bar in New York City's Greenwich Village, trigger violent protests in a seminal moment in the gay rights movement.
Singer and Christian conservative Anita Bryant spearheads a campaign in Florida's Dade County leading to the repeal of a local ordinance barring anti-gay discrimination.
Gay rights champion Harvey Milk of San Francisco's Board of Supervisors is shot dead along with Mayor George Moscone by a former city supervisor who is later cleared of murder charges, being convicted instead on lesser charges.
Wisconsin becomes the first state to prohibit discrimination based on sexual orientation.
The U.S. Supreme Court, in the case Bowers v. Hardwick, upholds a Georgia sodomy law, ruling consenting adults have no constitutional right to engage in homosexual acts even in private.
Hundreds of thousands of demonstrators march in Washington, faulting President Ronald Reagan's response to the AIDS epidemic and demanding more federal money for AIDS research and treatment. The U.S. AIDS epidemic in the 1980s disproportionately involved gay men.
The U.S. Supreme Court, in the case Romer v. Evans, throws out a Colorado measure approved by voters that denied gays protections against discrimination.
In a pivotal popular culture moment, the main character in Ellen DeGeneres' sitcom comes out as gay, just as the comedian herself had done.
The U.S. Supreme Court, in the case Boy Scouts of America v. Dale, decides the Boy Scouts can bar gays as troop leaders.
The U.S. Supreme Court, in the case Lawrence v. Texas, overturns its Bowers v. Hardwick ruling, throwing out a Texas sodomy law prohibiting two people of the same sex from certain sex acts.
Massachusetts becomes the first state to legalize same-sex marriages after a state court finds banning them violates the state constitution.
President Barack Obama signs a law repealing the 1993 "don't ask, don't tell" policy that had banned gays from serving openly in the U.S. military.
Obama becomes the first president to support gay marriage.
The U.S. Supreme Court, in the case United States v. Windsor, rules unconstitutional a 1996 law that declared for the purposes of federal benefits marriage was defined as between one man and one woman. Afterward, an increasing number of states allow gay marriage.
The U.S. Supreme Court agrees to decide whether states can ban gay marriage and sets arguments for April 28, with a decision due by the end of June.