Scottish ministers were commended across party bounds when the Marriage and Civil Partnership Bill was published two months ago and the Parliamentary arithmetic appears solidly in favour of the proposals.
But Scotland for Marriage is committed to stepping up its campaign, publicising its achievement in signing up 50,000 supporters across the country and pledging local campaigns in all 73 Holyrood constituencies.
The latest signatory was said to be Falkirk student Iain Donoghue, who argued there was no need to change the existing law and claimed opinion polls were on the side of those arguing against same-sex marriage.
But Green co-convener and MSP Patrick Harvie said the polling evidence said no such thing and said: "If they have these signatories, that's 50,000 people that I can now assure do not have to sign up to have a same sex marriage.
"At the end of the day, they are going to have to admit that the battle for lesbian, gay, bisexual and transgender rights is being won. Their continued opposition simply comes across as futile and mean-spirited."
He claimed the real purpose of the continuing campaign was to seek concessions in the legislation amounting to the reinstatement of Section 28 or repeal of anti-discrimination laws.
"That's just not going to happen," said Mr Harvie. MSPs will hold their Stage 1 inquiry next month with a Stage 2 debate likely in December and the final vote early in the New Year.