A report has suggested that three times as many three-year-olds living with single parents or step-parents have behavioral problems when compared to those living with married parents.
The aggressive pursuit of personal success by adults is now the greatest threat to British children, the major independent report on childhood also says.
The Children's Society conducted the work over three years, with 11 experts and more than 3,000 children and adults.
Their conclusions claim that excessive individualism in parents can have a negative impact on children.
The 'Good childhood' report blames adult selfishness for some of the problems afflicting children.
High family break-up rates, teenage unkindness, unprincipled advertising and too much competition are problems affecting childhood happiness, says the report.
It calls for a more caring ethic and less aggression.
The collapse of the family is also seen as a crucial factor in the raising of children, with women's financial independence seen as contributing to family break-ups.
It calls for professional family support if relations become difficult and free parenting classes around the time of a child's birth.
A significant redistribution of wealth and an increase in taxes to counter child poverty are other suggestions put forward.
Lord Layard, author of the report, told the BBC: "I think the best evidence is on [children's] mental health.
"A series of surveys. make it clear that the number of children suffering from mental health problems, disturbed emotions and disturbed behaviour has doubled between 1975 and 2000."
The European Social Survey found that trust between children in the UK is less than trust between young people in any other country in Europe.
Lord Layard continued: "It is more about how people treat each other and whether they think the advancement of their own interests is that important that it comes above trying to make your life of service to other people.
"What we think is that our society has become one where people are more focused on their own objectives and less on what they can contribute to other people.
"This can't produce a happier society. There is only so much success that can go round."
