A bid to change incest laws so they no longer apply to consenting adults over the age of 21 is to be considered by MSPs.
In a petition to the Scottish Parliament's Public Petitions Committee, Richard Morris argued the current law needs reform.
The campaigner also wants people who have been convicted under those circumstances to have their sentences reconsidered and potentially quashed.
He claims the current legislation "does unnecessarily and unfairly punish consensual adult incest, breaching the rights to sexual autonomy for all consenting adults that is accepted in other more developed countries".
In a submission to MSPs he stressed that adult consensual incest does not involve anyone under the age of 21, and added: "Therefore it involves only adults and excludes anyone under the legal age of consent, and even those a bit older who still may be psychologically immature, and vulnerable to abuse, but legally adults in every respect.
"Children are protected from sexual and other abuse by other laws, and there is no need for the double criminalisation of the offence."
Free Kirk Moderator, the Rev David Robertson, said: "Whilst it is currently 'unthinkable' and I am sure that MSPs will throw this petition out, this is just the first drop in what will be a drip, drip campaign by those who do not regard incest as unthinkable."
Committee convener Michael McMahon said: "I recognise the petition addresses a subject matter that many people find abhorrent. Speaking personally, I take a similar view.
"However, all petitions that fall within the committee's rules must be given our open and transparent consideration. It will be for the committee to decide if there can be any public interest in continuing this petition when we meet on Tuesday, January 26."