The Scottish Conservative leader was asked about his position on equal marriage in Tuesday night’s debate following a report in the Daily Record that he, while a councillor in Moray in 2014, had said he would have voted against the legislation had he been an MSP.
Told the legislation had made former Scottish Tory leader Ruth Davidson “cry with joy”, the Moray MP said it was now something “we should support”.
Asked directly whether he would have voted against the legislation that allowed gay people to marry their partners, Mr Ross said he had been “balancing both sides of the argument”.
He said: “I’ve said in a debate in Moray Council chamber that there was a passionate, engaged debate on both sides and I was balancing both sides of the argument because many constituents had contacted me.
"I said at the time I would have voted against it, just like two of Nicola Sturgeon’s ministers voted against it, but I have also said I fully support it.
"I think marriage is a thing of beauty both for men and women and people of same sex and I think it is something we should support.”
The response earned a stinging attack from Scottish Labour leader Anas Sarwar, who accused the Scottish Conservative leader of representing the “same old Tories”.
Referring to the apology around comments about the gypsy traveller community from Mr Ross at the previous debate on STV, Mr Sarwar said Scotland “deserves better”.
He said: “We’ve gone back to the same old Tories.
"The cuddly Tories under Ruth Davidson are well and truly gone.
"There’s a reason why Ruth Davidson has walked away, because Boris, we’ve got Boris, we’ve got Brexit, we’ve got chaos, we’ve got division, and not only is Douglas talking about same sex marriage, but he has already had to apologise for hateful views against other minority communities in Scotland.
"We are back to the same old Tories and frankly we deserve better.”
The leaders also clashed over accusations against Boris Johnson of sleaze and the alleged “pile the bodies high” comments made by the Prime Minister.
Mr Ross said he believed the Prime Minister following Mr Johnson’s denial that he said the comment, but attacked the comments themselves.
He said: “Those comments are unacceptable from anyone, whatever level of elected office or any individual at all and I would never support those comments, but the Prime Minister has said he did not make them.”
Responding, Nicola Sturgeon said she was “staggered” at what she described as “hypocrisy”, after Mr Ross and his party attempted to oust the First Minister over her government’s handling of harassment complaints against Alex Salmond before she had given evidence to that inquiry.
However, Ms Sturgeon was pressured over the SNP’s handling of their investigations into disgraced former finance secretary Derek Mackay by Mr Ross.
Willie Rennie, leader of the Scottish Liberal Democrats, said the competing claims of sleaze were “grotesque”, while Greens co-leader Patrick Harvie said the level of confidence in the UK Government had hit “rock bottom”.