The Church of England has risked the wrath of traditionalists by backing legal rights for large numbers of unmarried couples.
The Church is "sympathetic" to reform of the law for cohabiting couples where there are children involved, it has said.
It also suggests that more limited legal reform might be necessary for unmarried couples in cases not involving children where there is a risk of "manifest injustice".
The proposals are put in the Church of England's response to Law Commission recommendations which would allow unmarried couples the right to a share of each other's wealth in the event of a break-up.
The Church of England told the Law Commission that it believed marriage was central to the stability of health of human society and provided the best context for bringing up children.
But it said it believed there was a "strong Biblical precedent" for not only upholding standards but also protecting the vulnerable.
The Rt Rev Tom Butler, Bishop of Southwark, said: "It is perfectly jutified in terms of public policy for marriage to continue to confer particular benefits and privileges not available to those who choose not to commit to an enduring legal relationship, so long as adequate steps are taken to prevent manifest injustice.
"The test we would commend in assessing possible solutions is whether they will genuinely correct injustices without at the same time downgrading or creating disincentives to marriage."
The proposals come after the General Synod of the Church of England said two years ago that people living in relationships "not based on marriage" might face issues of hardship and vulnerability which needed to be addressed by new legal rights.
The Archbishop of Canterbury, Dr Rowan Williams, warned in June that plans to give legal rights to cohabiting couples would not reverse the decline of marriage.
Dr Williams said marriage had "suffered a long process of erosion" and the Law Commission proposals would further add to a "prevailing social muddle".
He said: "The concept of cohabitation is an utterly vague one that covers a huge variety of arrangements.
"As soon as you define anything, you are creating a kind of status that is potentially a competition with marriage or a reinvention of marriage.
"I think one of the problems is trying to solve individual and infinitely varied problems by legislation."
He said the proposals showed "very proper concern for vulnerable people who are left stranded at the end of a partnership breaking up" but he said those "anxious" about the needs of a cohabiting partner could already make wills and legal contracts.Reuse content