In the days since Senator Rob Portman came out in support of gay marriage, other prominent Republicans have been asked if their position might also change on the issue.

Rick Santorum, one of the most outspoken opponents of gay marriage and LGBT equality in mainstream politics, said over the weekend that he is ‘not changing my opinion on that issue.’

‘Marriage is a thing of nature,’ Santorum said. ‘Men and women come together and form the bond by which to raise the next generation. No other relationship – you can call it marriage – but no other relationship accomplishes what real marriage accomplishes.’

Santorum is a former US senator from Pennsylvania who finished second overall behind Mitt Romney in the Republican presidential primaries.

He, once again, grouped gay marriage in with polygamy.

‘If you want to change what marriage is, if marriage is just two people loving each other, or three or four people loving each other you can call anything marriage,’ he said. ‘But that’s not what marriage is. Marriage is something of nature. It’s something that every civilization in the history of man has recognized as a very valuable bedrock of society. Just because people change their mind doesn’t make anything less so.’