Chelsea Clinton, the daughter of former president Bill Clinton, has spoken out in support of gay marriage.

Speaking at a New York benefit for charity Friendfactor, she said that straight people should join the fight for equal rights.

Clinton, who attended with her husband Marc Mezvinsky, said: “I certainly believe that all of my friends, as Marc and I did, should have the right to marry their best friends.

“I certainly believe that those of us who are straight cannot expect our gay friends to do this on our own.

“And I certainly expect our straight friends to help us achieve that for all New Yorkers, for all Americans, and for all the children that at least Marc and I hope to have someday.”

The pair, who announced their engagement in 2009, married last August.

While Bill Clinton has openly backed gay marriage, his wife, secretary of state Hillary Clinton, has not.

During an interview last year, she would only say she had not changed her position.