John McCain says he doesn’t think he’ll be following the lead of fellow Republican Senator Rob Portman, who stunned so many last week when he announced his support for equal marriage.

Mr Portman said he had changed his views after realising that his 21-year-old son, Will, was gay.

The Ohio lawmaker was staunchly against equal marriage until 2011. He co-sponsored the federal Defense of Marriage Act – which banned federal recognition of same-sex marriages.

Mr McCain, who ran against Barack Obama for the presidency in 2008, told CNN’s Anderson Cooper last Friday that he wouldn’t be changing his mind, as the issue is at odds with his beliefs.

“I respect anyone else’s decision and we all learn in life and grow and mature. I have changed my position on other issues in my life, but on this one, I had not contemplated changing my position,” he said.

Other members of McCain’s family, his daughter, Meghan, and wife, Cindy, have made public statements urging the Republican Party to abandon its opposition to marriage equality.

Cindy McCain joined the NOH8 campaign against California’s equal marriage ban in 2010.