Joint responsibility agreements, joint mortgages and shared registering of children are the features of a new approach for those who wish to avoid marriage but who are, to all intents and purposes, as closely linked as a couple who walk down the aisle.
Alistair Burt, the Social Security Minister, may have been on safe statistical ground when he attacked the increasing instability of family life induced by high divorce rates and rising cohabitation. But enthusiasm for marriage as the vehicle to deliver stability flies in the face of the trends of family relationships and founders on a lack of evidence of whether an unhappy marriage is better or worse for children than divorce.
David Rose, assistant director of the British Household Panel Study, which Mr Burt used to back up his case, was cautious about drawing the same conclusions. 'There is absolutely nothing in our data to suggest a moral panic over cohabitation,' he said. 'If the concern is the welfare of children, then 80 per cent of the children involved in the break-up of relationships come from married couples.'
Mr Burt correctly stated that cohabitating couples were four times more likely to separate. But the figures include all cohabitating men and women, including young couples living together before marriage, as well as divorced people in a second relationship.
Mr Burt also said that couples living together before marriage were twice as likely to experience divorce or separation as couples who did not. 'The decline of marriage as an institution and the increase in cohabitation are to be regretted if it results in more separations and in more relationships breaking up,' he declared.
Mr Rose, whose study involves long-term tracking of 10,000 people, said two-thirds of those marrying between 1985 and 1992 had lived with someone before marriage. The majority had at least lived with their marriage partner. 'For a lot of young people cohabitation is replacing a long engagement. But there is still a tremendous commitment to the family. Perhaps the problem is that we expect too much of relationships and the family,' he said.
Britain is at the forefront of family changes in Europe with high divorce and cohabitation rates. Only Scandinavian countries have higher levels of cohabitation while Britain has the highest rate of divorce with an expectation that about 40 per cent of today's marriages will end in separation.
At the other extreme, fewer than 3 per cent of Italian couples cohabitate and less than 10 per cent of marriages in Spain and Italy end in divorce. The One Plus One marriage research charity said: 'Variations in the rates of marriage, cohabitation and divorce in the European Union are embedded in cultural differences, especially differences associated with religion and the relationship of church and state.'
The changes in Britain have meant a steady rise in the number of illegitimate births, now making up nearly one-third of all newborn children.
Penny Mansfield, deputy director of One Plus One, said there were two distinct groups of cohabiting women who had children. 'There is the 16-year-old who runs away from home . . . and moves in with her boyfriend and has a baby,' she said.
'And there is the 35-year-old woman who is well educated, has a good job and who deliberately decides to have a baby.'
The second type of woman is the most likely to introduce joint responsibility agreements with the child's father. The birth is likely to lead to an acceptance by the couple's families of their relationship as 'real', rather than being considered unstable.
Research published earlier this year from the Family Policy Studies Centre made it clear that family disruption, including separation and divorce, had a damaging effect on children. However, the illegitimate offspring of single women who did not live with their partner fared better than those whose parents lived together.
The British Household Panel Study is expected to follow up outcomes for children in future years to answer the question posed by the Family Policy Studies Centre: 'The evidence suggests that children do not generally thrive where their parents' marriage is characterised by conflict.'
Denise Knowles, a counsellor with Relate, said she had not noticed any difference in the approach of married and non-married parents. 'During the breakdown of a long-term cohabitation the partners stress that it was just like a marriage,' she said.