Muslim leaders from Scotland's biggest city have voiced their opposition to gay marriage.
The Scottish government has been consulting on whether to bring in a law which would allow churches to hold same-sex wedding ceremonies.
The Council of Glasgow Imams said such a legal move would be an "attack" on their faith and fundamental beliefs.
The views of the Islamic clerics are in keeping with those of the Catholic Church and the Church of Scotland.
Five smaller church groups have expressed their backing for a change to the law.
Currently, same-sex couples can enter a civil partnership which carries full legal rights but the ceremony cannot be conducted in a church or other religious premises.
The Council of Glasgow Imams said the "main purpose of marriage is, of course, the procreation of children" and that because gay couples had been "accommodated" through the legalisation of civil partnerships, there was "no need for such unions to be blessed as marriages by faith institutions".
The council is based in Glasgow but the message is being sent to Muslims all over Scotland.
In January this year political leaders signed a pledge to support a campaign to legalise same-sex marriage.
Leaders of the Labour, Liberal Democrat, Green and Conservative parties signed up at an event at Holyrood which was marked with a specially created "equal marriage" cake.
The Scottish government held a 14-week public consultation on the issue and said it "tends towards the view" that same-sex marriage should be introduced, but that faith groups and their celebrants should not be obliged to solemnise the ceremonies.
In their statement the Glasgow imams urged people in their community not to vote for any candidate who supported same-sex marriage in May's council election.
It said: "This resolution has been prepared by the imams (religious leaders) of the Muslim community following lengthy discussions which have taken place to address deep concerns in our community. Furthermore, we must now make it clear that in the following days, preceding the local authority election in Scotland on Thursday May 3 we will be urging our community from the pulpit to make sure that any person they consider voting for does not favour the proposed legislation."
It went on: "A family is a man and a woman and children. If the government turns a family into a man and a man or a woman and a woman with no procreative faculties, what would become of our society, our civilisation? This is a serious question that deserves very serious consideration by the Scottish government. Accordingly, we urge the Deputy First Minister Nicola Sturgeon to look very seriously at this fundamentally important issue and to reconsider the full implications of what she is proposing."
"We wish to inform both her and First Minister Alex Salmond that we are deeply unhappy and vigorously opposed to the proposed legislation for same-sex marriage. There is no scope for compromise on this issue and we simply say this: No to same-sex marriage."
A Scottish government spokesman said: "The consultation on same-sex marriage and registration of civil partnerships has now closed and we are now analysing the responses and considering what next steps to take. As was made clear when the consultation was launched, while we have expressed our initial view, we have given an assurance that all opinions will be listened to, no final views have been reached and therefore no decisions have been taken. The analysis of the responses will be published later in the spring."