All the legal rights of marriage are already available to homosexual couples through civil partnership registrations. Last year only 465 civil partnerships were registered in Scotland.

This is not about rights, this is about redefining marriage for the whole of society at the behest of a small minority of activists.

If marriage is redefined for homosexual marriage, that new definition will be the one that the state promotes as the standard. It will have huge implications for what is taught in schools and for wider society.

If marriage can be redefined for homosexual marriage, why not redefine it to allow polygamy? Canada has legalised homosexual marriage, and litigation is now underway in one Canadian state to legalise polygamy.

Marriage, although undermined by easy divorce and cohabitation, remains a key building block of society. Children do best when they have a mother and a father who are committed to each other. Children need a mother and a father, but homosexual marriage denies this.

As Michael White of the Guardian has said, no amount of technology can ‘eliminate the need for a female egg and a male sperm to make a baby. On that fact rest all successful societies since the year dot’.

Alex Salmond has repeatedly said the Scottish Parliament does not have sufficient powers to deal with the tax, pension and immigration implications of redefining marriage. Only a fully independent Scotland could truly redefine marriage with all the knock-on implications.

Some homosexuals regard marriage as a patriarchal institution and would rather retain civil partnerships. For similar reasons, some heterosexuals wish to enter a civil partnership rather than a marriage. If civil partnerships were retained alongside homosexual marriage, the cost to the state could be huge.

If the situation was extended to the whole of the UK Ben Summerskill of Stonewall estimated the loss in tax revenue at £5bn. And there would be an injustice against unmarried siblings who share a house and take care of each other.

The separate idea of allowing churches to register homosexual civil partnerships is a complex legal proposal and a religious liberty minefield. There will undoubtedly be legal actions taken against churches that choose not to allow their premises to be used.

The Westminster Government, which is drafting similar proposals for England and Wales, has already accepted this.