London: Nine out of 10 babies born to co-habiting parents this year will have seen their family break up by the time they reach the age of 16, says a study.

Half of all children born this year will not be living with both natural parents when they reach their mid-teens, and almost all those who suffer family breakdown will be the children of unmarried parents, added the report.

The study, based on figures from the national census and large-scale academic surveys, extrapolates from current trends and calculates that just nine per cent of babies born to cohabiting couples today will still have their parents living together by the time they are 16.

The report adds that the declining popularity of marriage and the rise of co-habitation will damage the lives of increasing numbers of children.

The figures were produced by researcher Harry Benson, of the Marriage Foundation think tank, who said: “The report provides solid evidence that married parents are more stable than unmarried parents.

“The contrast between married and unmarried parents who remain intact by the time their children reach their teenage years demonstrates that marital status plays a crucial role in family breakdown.

“With family breakdown costing an estimated £46 billion a year - more than the entire defence budget - in addition to the immeasurable social damage, it is clearly in the interest of the government and the taxpayer to work to counter this devastating trend.’

The study by the think tank, which is headed by High Court family division judge Sir Paul Coleridge, was based on findings from the census of 2001 and recent results from Understanding Society, a government-backed survey which charts the lives of people in 40,000 homes.

The report said that in 2001, four out of 10 teenagers aged 15 were not living with both parents, and among the parents of 15-year-olds who stayed together, 97 per cent were married.

Understanding Society, a ‘longitudinal’ survey which asks questions of the same group each year, found that 45 per cent of teenagers aged between 13 and 15 are not living with both parents. It also found that of the parents who were still together, 93 per cent were married.