Married parents are best, admits Blairite think tank

A stable background means they are less likely to be out of work, live off the state, become single parents, or even smoke in later life, according to the Institute for Public Policy Research.

It said it also accepted that children are better off with married parents than with parents who cohabit.

The report from the country's most prominent and influential Left-leaning policy group contradicts eight years of Government rhetoric saying that all families are equally good.

Billions of pounds have been targeted at single parents while ministers have undermined the legal and social status of marriage, according to critics.

But yesterday the policy institute acknowledged that research clearly showed that 'children who grow up with both biological parents do better on a wide range of outcomes than children who grow up in a single-parent family'. It added: 'While this research may be instinctively difficult for those on the Left to accept, the British evidence seems to support it.'

The climbdown came in the think-tank's report on youngsters. This revealed that our teenagers drink more, take more drugs, have sex at a younger age and are involved in more fights than those elsewhere in Europe.

And yesterday - when the institute made its full report available - it said the breakdown of the traditional married family was at the root of this disturbed teenage behaviour. It said: 'Changes to families, such as more parents working, and rising rates of divorce and single parenthood, have undermined the ability of families to effectively socialise young people.'

Noting that 'changes to family structures are significant', it referred to unpublished research that compared the lives of 30-year-olds who were in single-parent families at the age of 16 with those whose parents stayed together.

It said they were five per cent more likely to be unmarried, 1 per cent more likely to be a single parent and 2 per cent more likely to be in social housing. They were also more likely to rely on benefits and live in a home where no one worked.

The report said: 'Single parents, it has been shown, can be less emotionally supportive, have fewer rules, dispense harsher discipline, are often more inconsistent in dispensing discipline, provide less supervision, and engage in more conflict with their children.'

The institute cited the Millennium Cohort Study, a survey by the Institute of Education in London of nearly 20,000 children born in 2000.

This, it said, 'has shown that children of cohabiting couples do worse than those of married couples.'

The IPPR report drew praise from research groups that have been reporting on the fallout from the decline of marriage in Britain.

Robert Whelan of the Civitas thinktank said: 'I am pleased they have come round to what we have been saying for 20 years.

'It is difficult to find any evidence that supports any other view. But to say there is nothing we can do about it is a counsel of despair.

'The Left believes state intervention is morally right and can change people's behaviour in areas like smoking and environmental pollution.

'Why won't it work if you change the benefit system so that it stops penalising couples and encouraging single parenthood?'

Jill Kirby, of the Right-leaning think-tank Centre for Policy Studies, said: 'The IPPR has been forced to acknowledge what has happened by the weight of evidence. But they are wrong to conclude there is nothing we can do. This is a Government that sees nothing morally wrong in giving instructions over every aspect of how to raise children.'

Ministers have encouraged mothers of young children to take jobs and described those who do not as a 'problem'. They have laid down instructions on how nurseries should train children almost from birth.

And Mr Blair has proposed state intervention into the lives of children from troublemaking families even before they are born.