The Church of Scotland will decide on whether to allow minister to carry out gay weddings later today.
A proposal going before the Kirk's general assembly calls for an apology for past discrimination of LGBT people and recommends individual churches have the freedom to decide whether to marry same-sex couples.
The recommendation, made by the Church's Theological Forum, insists there must be protections for 'conscientious refusal' from conservative clergy but evangelicals fear the move could lead to all ministers being forced to take gay weddings, even if it is against their beliefs.
'We recognise that as a Church we have often failed to recognise and protect the identity and Christian vocation of gay people and believe that the Church as a whole should acknowledge its faults,' said former Church moderator Professor Iain Torrance, convenor of the Theological Forum.
'In years past there has been an idea that in time one side in this argument would emerge as the sole victor.
'We don't think like that now,' he said.
'That is why we are arguing for what, last year, the Forum called "constrained difference". This is saying that within limits we can make space for more than one approach.
'It is closely similar to what the Archbishop of Canterbury calls "mutual flourishing".
'This is a centrist report, aimed at encouraging mutual flourishing.'
The Presbyterian Church of Scotland's debate coincides with the Anglican Scottish Episcopal Church, which will debate changing its doctrine on marriage to remove references to 'man and woman' next month.
The Church is expected to approve the change in doctrine sent to its seven dioceses for discussion last year.
Those who do not wish to conduct a same-sex marriage will be able to opt out via a conscience clause.
Same sex marriage has been legal in Scotland since the end of 2014 but as in England, most churches at present do not conduct them.
If passed it would mean the Scottish Episcopal Church becomes one of the first Christian denominations in Britain to agree to marry gay and lesbian couples, and will add to the strains currently dividing the worldwide Anglican Communion.
