The Church of England is to offer engaged couples who already have children an infant baptism service alongside their marriage ceremony.
The bride and groom will move from exchanging vows and giving the ring to presenting their child for baptism.
Critics warned the plans could “confuse” people about Christian teaching and encourage them to take marriage and baptism lightly.
The service was laid out by the Church of England’s liturgical commission.
Its chairman, the Bishop of Wakefield, the Rt Revd Stephen Platten, said: “I don’t think we are condoning cohabitating couples. What we want to do is not to reject them. We want to encourage them to marry to show their commitment to each other and to safeguard a stable society.”
However David Phillips, General Secretary of the Church Society warned that combining the services may not be a good idea.
He said: “Putting these services together seems unwise. The proper place for sex is within marriage. That should be what people are taught when seeking baptism.”
And Simon Calvert of The Christian Institute said: “Forgiveness is central to the Christian gospel, but it depends on repentance, and we would expect the services to contain an expression of repentance for what the Book of Common Prayer calls ‘fornication’.
He added: “The Church is made up of forgiven sinners, but without proper explanation these services could be seen as a quick-fix for the problems created when people have children outside of marriage instead of taking time to deal pastorally with all the issues.
“There is a danger that this could be seen as a stamp of approval from the Church on a lifestyle choice which runs against the teaching of the Bible.”
Research for the Archbishops of Canterbury and York found that increasing numbers of couples marrying in church already had children.
In guidelines for the new service, the Church of England makes clear that infant baptism and marriage services are best carried out separately, but that a minister can combine the two if it is in the interest of the couple.
It says Communion can also be included but “serious consideration” should be to the “overall length of the service, and the potential confusion arising from an overload in terms of imagery.”
Clergy will not be required to perform the services if they have doubts about the biblical basis for them.