New York approves gay marriage and teaches the world a lesson.

Same-sex marriage is now legal in New York State after Governor Andrew Cuomo signed the bill that passed the legislature by a narrow margin on Friday. This is a huge victory for activists in the state, where the gay rights movement was born.

New York has become the sixth state where gay couples can marry.

Gay rights advocates hope the vote will spur the movement across the country and help revive the fight, after a nearly identical law was defeated in New York in 2009 and similar attempts also failed in other states in recent years.

The effects of the legislation will be felt beyond New York. Unlike Massachusetts, the first state to approve gay marriage in 2004, New York does not require proof of residency to obtain a marriage license, meaning the state could become the preferred location for same-sex couples from across the country.

New York, the third most populous state in the United States, is now part of the group that includes Connecticut, Iowa, Massachusetts, New Hampshire, Vermont, and the capital, Washington, where same-sex couples can marry.

"Once the law is passed, the population of the United States living in marriage-equal conditions will double," said Ross Levi, executive director of the LGBT group Empire State Pride Agenda, in an interview. "This will certainly have a ripple effect across the country. This is truly a historic night for love. Our families and democracy have won."

Although New York City passed the measure somewhat late, the law is considered an important achievement by gay rights advocates, given the size of the state and the international prominence of New York City.

The gay rights movement is considered to have begun with the Stonewall Inn riots in Greenwich Village, New York City, in 1969. A huge street party started outside the Stonewall Inn on Friday night, with participants waving rainbow flags.