Former SNP MP Mhairi Black has said the views of Kate Forbes on gay marriage are “archaic” and “quite extreme”.
The former MP for Paisley and Renfrewshire South said the Deputy First Minister’s views risked alienating young people.
In an interview with The Sunday Post newspaper, Ms Black also said the SNP needs to “get its house in order”, suggesting debate within the party had been stifled.
She spoke ahead of the start of her run of Edinburgh Fringe shows, which are titled Politics Isn’t for Me.
Ms Black told the newspaper: “We all remember Kate Forbes’ interview where she said she wouldn’t have supported gay marriage and doesn’t think people should have kids out of wedlock.
“Basically really archaic and, in my opinion, quite extreme views.
“That is out of step with what the SNP has stood for and where the SNP has attracted so much support. It’s because it has been this progressive force.
“It has been wanting to take Scotland into the 21st Century and wanting to be inclusive.
“If you then start endorsing the sort of views Kate Forbes was saying, voluntarily, on camera, then that’s a massive red flag to so many people – particularly young people.”
She added: “The truth is independence won’t happen without young people and certainly support for the SNP and success for the SNP won’t happen without young people on board.”
Ms Forbes’ religious views caused controversy during the race to succeed Nicola Sturgeon as first minister, after she said she would not have voted for gay marriage had she been an MSP at the time.
Ms Black, who stood down as an MP at the General Election, also said John Swinney needs to be “real and brutal” about the change needed in the SNP.
She said: “Basically the party needs to get its house in order and that’s not going to happen unless there is real commitment to it and the leader is making it happen.”
There had been a reluctance to talk about anything “uncomfortable” within the SNP, she said.
Commenting on MS Black’s remarks, an SNP spokeswoman said: “The SNP has consistently been a moderate, left-of-centre political party that is resolutely focused on delivering for the people of Scotland.
“Whether it’s free prescriptions, free tuition or the game-changing Scottish Child Payment, we are determined to build a better Scotland and work towards Scottish independence.
“Our key priorities of eradicating child poverty, promoting economic growth, ensuring our public services are sustainable and tackling climate change are also those of people across Scotland, and we are committed to delivering on those priorities.”
