Scottish Liberal Democrat leader Willie Rennie has urged the government not to be swayed by Catholic threats over gay marriage.
While the SNP government says it is inclined to back marriage equality, Catholic leaders say it will lose the support of 800,000 Catholics if it presses ahead with the proposals.
The government is holding a 14-week consultation on the issue but Bishop of Paisley Philip Tartaglia, who is expected to become the next Archbishop of Glasgow, claimed yesterday that Catholic voters would desert the SNP if marriage equality becomes a reality.
Church leader Cardinal Keith O’Brien said the change would be a “grotesque subversion of a universally accepted human right” and that gay parents cannot adequately bring up a child.
Mr Rennie, said: “I am disappointed that leaders of the Catholic Church in Scotland have threatened the Scottish government over proposals to bring equality to marriage.
“Over six in ten people support same-sex marriage, so to threaten politicians with the votes of 800,000 people of the Catholic faith may backfire on the church.”
He added: “Ten years ago politicians stood firm against the Catholic Church and others when they threatened the parliament over Section  equality teaching, I hope the Scottish parliament stands for what is right and fair again.”
Although ministers have stressed that churches would not be forced to hold gay marriage ceremonies, religious leaders claim they will be at risk of legal action if they do not welcome gay couples.
As with the rest of the UK, Scotland allows gay couples to have civil partnerships. Gay rights campaigners are pushing for full marriage equality.
Last year, a poll of more than 800 PinkNews.co.uk readers found that 98 per cent wanted the right to marry.