SAN FRANCISCO: The US Supreme Court considers two same-sex marriage cases on Tuesday and Wednesday, one on a marriage ban in California and another on a federal law that restricts the definition of marriage to a man and a woman.

Following is a timeline of main events leading up to this hearing.

1969: The modern gay liberation movement unofficially kicks off with the Stonewall Riots, demonstrations by gays in response to a police raid in New York City.

1972: The US Supreme Court lets stand a Minnesota Supreme Court ruling that the law does not allow for same-sex marriage, and that the issue is different from interracial marriage.

1973: Maryland becomes the first state to pass a statute banning gay marriage, according to Freedom to Marry.

1977: Harvey Milk becomes first openly gay elected official in San Francisco, wins seat on Board of Supervisors. He later appeals to gays to come out and run for office, “for invisible, we remain in limbo.” Milk was shot and killed in 1978.

1986: US Supreme Court says “we are quite unwilling” to find a fundamental right to sodomy, even in the privacy of one's home, in Bowers v. Hardwick.

1996: US Supreme Court Justice Anthony Kennedy, often called the swing vote on the court, writes opinion striking down Colorado ban on protections for gays, saying the ban “seems inexplicable by anything but animus.”

President Bill Clinton signs Defense of Marriage Act, defining marriage as between a man and a woman for federal purposes (which he now says should be overturned).

1997: Comedian Ellen DeGeneres reveals she is gay. Shortly afterward her sitcom character says “I'm gay” - inadvertently speaking into an airport public address system.

1998: Debut of television show “Will and Grace”, about a gay man and his best friend, a straight woman.

2000: Vermont becomes the first US state to allow civil unions for same-sex couples. Republican Vice Presidential candidate Dick Cheney, who has a lesbian daughter, indicates he supports gay marriage, saying “freedom means freedom for everybody” and that “people should be free to enter into any kind of relationship they want to enter into. He said states should regulate the matter, not the federal government.

Queer as Folk was the first hour-long drama on American television to portray the lives of gay men and women, and the only one which ran for five seasons till 2005.

2003: US Supreme Court, in another decision written by Kennedy, strikes down Texas anti-sodomy law in Lawrence v. Texas and reverses the 1986 Bowers ruling. Kennedy writes that this doesn't mean the government must recognize gay relationships.

“Do not believe it,” Justice Antonin Scalia dissents, saying the logic of the opinion points to allowing same-sex marriage.

The Massachusetts Supreme Court rules in favor of same-sex marriage, and gay weddings begin in 2004.

2004: San Francisco Mayor Gavin Newsom directs county to allowing same-sex marriages, arguing the state's voter-approved ban on gay marriage, Prop 22, was unconstitutional. The state Supreme Court stops the weddings on grounds unrelated to the constitutionality of marriage.

2005: Canada allows gay marriage.

2008: California gay marriages become legal when the California Supreme Court strikes down the Prop 22 ban. That November voters add a ban to the state constitution - Prop 8 - ending a summer of gay marriage.

2009: Iowa State Supreme Court legalizes same-sex marriage. It is still the only Midwest state that allows gay marriage.

Federal court challenge to Prop 8 filed, days before California Supreme Court lets Prop 8 stand as a valid change to the state constitution. Eventually, federal district and appeals courts agree to strike down the ban, which is now before US Supreme Court.

2011: President Barack Obama's administration ends “don't ask don't tell policy,” allowing gays to serve openly in the military.

2012: North Carolina approves a constitutional amendment to ban gay marriage in May. In November, Maine, Maryland and Washington become the first states where voters approve same-sex marriage, and Minnesota rejects a new ban.

President Barack Obama endorses same-sex marriage.

2013: Boy Scouts of America plan to vote in May whether to repeal the group's ban on openly gay members.

US Supreme Court on March 26 and 27 hears oral arguments on the constitutionality of California's Prop 8 and the federal Defense of Marriage Act. At this point nine states and the District of Columbia allow same-sex marriage and 38 states prohibit it, according to Freedom To Marry.