US President Barack Obama has ended months of hedging on the issue of gay marriage by saying he thinks same-sex couples should be able to wed¹.

美国总统奥巴马对近期热议的同性恋婚姻表达了自己的态度，他认为同性恋情侣应该能够成婚。

He has become the first sitting US president to back gay marriage.

Mitt² Romney, the Republican who is set to challenge Mr Obama for the White House in November's elections, promptly³ said he was against gay marriage.

In recent days, Vice-President Joe Biden and cabinet member Arne Duncan had expressed support for gay unions.

A Gallup poll on Tuesday suggested that 50% of Americans were in favour of legalising gay marriage - a slightly lower proportion than last year - while 48% said they would oppose such a move.

The interview with ABC News was apparently⁴ hastily arranged as Mr Obama came under mounting pressure to clarify his position on the issue.

"At a certain point, I've just concluded that for me personally it is important for me to go ahead and affirm that I think same-sex couples should be able to get married," Mr Obama told ABC.

He pointed⁵ to his administration's commitment to increasing rights for gay citizens. He cited the repeal⁶ of the military's "don't ask, don't tell" policy and said his administration had dropped support for the Defense⁷ of Marriage Act.

"I've stood on the side of broader equality for the LGBT community. I hesitated on gay marriage in part because I thought civil unions would be sufficient," Mr Obama said.

He said he had changed his views after seeing gay members of his own staff who were in "incredibly committed monogamous（一夫一妻的） relationships", and service personnel who felt constrained⁸ by not being able to wed.

Mr Obama also said discussions with his own family had helped the "evolution" of his views on the issue.

"There have been times where Michelle and I have been sitting around the dinner table and... Malia and Sasha, it wouldn't dawn on them that somehow their friends' parents would be treated differently," Mr Obama said.

"It doesn't make sense to them and frankly⁹, that's the kind of thing that prompts a change in perspective."