Britons are increasingly likely to live in single-parent families, stay at home for longer, marry later and struggle to afford a house, official figures show.
Two-parent households are becoming less common
The Office for National Statistics said children in the UK were three times more likely to live in one-parent households than they were in 1972.
Last year almost 60% of men and 40% of women aged between 20 and 24 in England still lived with their parents.
The department's annual Social Trends report studies patterns in UK society.
Among the findings this year was that wages rose on average by 92% from 1995 to 2005, but house prices rocketed by 204%.
Stephen Evans, chief economist with the Social Market Foundation, said problems getting on the property ladder were partly to blame for young people leaving home later, but insisted there was an element of choice involved too.
"They're making a choice to extend their education because they know that they're going to get higher earnings in the long run."
Since 1971 the proportion of all people living in "traditional" family households of married couples with dependent children has fallen from 52% to 37%.
Over the same period, the proportion of people living in couples with no children rose from 19% to 25%.
Nearly a quarter of children lived with only one parent last year and nine out of 10 of those households were headed by lone mothers.
David Green, director of the Institute for the Study of Civil Society, told BBC Radio 4's Today programme: "If you take almost any measure - how well children do in school, whether they turn to crime, whether they commit suicide, etc - it's better to have two parents.
"It's also the biggest disadvantage of lone parenthood that you're much more likely to be poor."
SOCIAL TRENDS SURVEY
In 2005 there were a record 60.2m people living in the UK
The number of households has risen 30% since 1971, but the population only rose by 8%
One in seven children live in households where no parent is working
Source: Office for National Statistics
But Jane Ahrends, from One Parent Families, said while single parents might face poverty, the image of them as "young, feckless women who deliberately get pregnant" was wrong.
"The vast majority of lone parents are ordinary working mums and dads in their 30s and 40s, who are just trying to do their best in circumstances they didn't choose," she said.
"And remember, families are constantly changing - lone parenthood is not a permanent state for most people. It's a phase, usually lasting about five and a half years."
More children are born in Britain today outside of marriage than in most other European countries, the report also said.
The average figure is 44%, compared with just 3% in Cyprus, and just 12% in Britain in the early 1970s.
BBC home editor Mark Easton said that in Wales and the north east of England the numbers of children born to unmarried parents were even higher, at 52% and 55% respectively.
More than seven million people in Britain also live alone now, compared with three million in 1971.
This, the report said, had left societies more fragmented and led to much less trust and co-operation between neighbours.
Other findings included:
Second marriages made up two-fifths of all marriages in 2005.
In the same year, the average age at first marriage in England and Wales was 32 for men and 29 for women - up from 25 and 23 respectively in 1971.
Divorces in 2005 fell to 155,000 from a 1993 peak of 180,000.
In 2005, 66% of single-parent families lived in rented housing compared with 22% of couples with dependent children.