A US Senator who was among the original sponsors of the Defense of Marriage Act (DOMA) has announced that he has changed his anti-equal marriage stance, following the personal revelation of his own son’s coming out as gay.

Ohio Republican Rob Portman, previously rumoured to be in the running for Vice President during Mitt Romney’s 2012 campaign, told CNN he had been deliberating on the issue since his son came out to him as gay two years ago.

Will Portman, 21, came out to his parents while in his first year at Yale University.

“My son came to Jane, my wife, and I, told us that he was gay, and that it was not a choice, and that it’s just part of who he is, and that’s who he’d been that way for as long as he could remember,” said Mr Portman, adding that the coming out was a complete surprise to him.

Since then Mr Portman had been reconsidering his views, but had kept this, and his son’s sexuality, largely a secret.

Now, with the Supreme Court poised to hear an appeal on DOMA later this month, Mr Portman has made his change of heart known publicly.

“I’ve come to the conclusion that for me, personally, I think this is something that we should allow people to do, to get married, and to have the joy and stability of marriage that I’ve had for over 26 years. That I want all of my children to have, including our son, who is gay,” he said.

He added his son supported the decision, as well as the decision to effectively out him to the world.

Prior to his son’s coming out, Mr Portman had consistently acted in opposition to gay rights issues during his political career.

In 1996 he was one of the co-sponsors of DOMA, which nationally defined marriage as being between a man and a woman. The Supreme Court will later this month consider an appeal against Act, urged on by President Obama and even Bill Clinton, the former President who signed DOMA into US law. 

Mr Portman also voted against allowing gay couples in Washington to adopt children.

In 2011 students at the University of Michigan protested against Mr Portman’s anti-gay rights stance by walking out of his commencement address. This was shortly after Mr Portman had learned own son was gay, and he said he found the experience “odd”.

One of the few people he talked to about his evolving views on same-sex marriage was former Vice President Dick Cheney. Mr Portman said Cheney told him, “follow your heart”.

“He was a good person to talk to because he also was surprised by the news, in that case, you know, his wonderful daughter, who he loves very much. And it forced him to re-think the issue too, and over time, he changed his view on it,” said Mr Portman.

As well as the appeal on DOMA this month, the Supreme Court will also consider overturning Proposition 8, which bans same-sex marriage in California.