Poverty in childhood is a far bigger cause of unhappiness and mental illness in later life than living in non-traditional homes such as single-parent families or stepfamilies, according to new research.

The findings undermine the popular view that the growth in single- parent families and escalating divorce rates over the past 30 years are unravelling Britain’s social and moral fabric. Particularly surprising was the finding that children of divorced parents are as content in later life as those whose parents stayed together.

The research uses data collected for the National Child Development Study, which has been tracking the lives of 17,000 people from birth to age 33. The researchers explored the relationship between parental background and adult “outcomes”: their satisfaction with life, emotional well-being, amount of family conflict and views about parenting.

The risk of psychological problems at 16 and depressive tendencies at 33 were markedly greater for children who had been taken into care or had lived in squalid housing. Being in care had the worst impact on men, while women were most affected by poverty.

Those who had grown up in traditional families with both natural parents were not significantly happier with their lives at 33 than those with divorced or widowed parents. Levels of contentment for people from other single-parent families (such as unmarried mothers) were more variable, but far higher than for those who had been in care or very poor. The study also found that children do not bring the happiness hoped for by their parents. Women who had children before the age of 23 were significantly less satisfied with their lives than those without, while at 33, men and women who had become parents were no happier than the childless. The researchers suggest that this finding may reflect the stresses experienced by working parents.

All the participants tended to take a liberal attitude to family arrangements. Seven out of 10 thought having children outside marriage was acceptable, and most disagreed with the statement that “couples who have children should not separate”. Children of lone parents expressed the least support for traditional marriage. The better educated were also less wedded to tradition.

The research, sponsored by the Joseph Rowntree Foundation, follows findings from the Office for National Statistics last week which suggested that while family life is as important as ever, family structures are becoming increasingly diverse and the number of poor families is increasing.