It might be better for policy makers to encourage part-time employment by one parent during a child's pre-school years

Professor John Ermisch, Institute for Social and Economic Research

Researchers followed the academic progress of pupils born in the 1970s and have found that low attainment was more likely in families where mothers returned to full-time work before children were five.

The long-term study for the Joseph Rowntree Foundation, based on over 1,200 young people, says that where mothers went back to full-time work children were less likely to achieve A-levels.

There were also links between both parents of pre-school children working full-time and an increase in psychological problems in adulthood.

Although the working patterns of fathers exerted an influence on pupils' achievement, researchers claimed that maternal employment had a much greater impact.

But where a parent was working part-time these negative associations were much less pronounced, leading researchers to query the benefits of welfare-to-work schemes which emphasised full-time employment.

"It might be better for policy makers to encourage part-time employment by one parent during a child's pre-school years," said report co-author Professor John Ermisch of the Institute for Social and Economic Research.

For many mothers full-time work is a necessity, not a lifestyle choice. I hope this research won't be used as another stick to beat them

Mary McLeod, National Family and Parenting Institute

According to the research, where a mother of pre-school children worked full-time for a year longer than the average 18 months, there was a fall of 12% in the likelihood of that child gaining A-levels.

And there was a 2% increase in the likelihood of unemployment and 5% increase in the incidence of stress among children of full-time working mothers when they became adults.

Among children with mothers working part-time, there was a 6% drop in A-level attainment, but also a 2% lower likelihood of psychological problems.

"This is evidence in support of employment policies such as parental leave and longer maternity leave. Entitling parents to more time with young children can be justified as a potential investment in the labour force of tomorrow," said Professor Ermisch.

'Exaggerated'

But Sue Tibballs, an executive member of the Fawcett Society which campaigns for equal rights - herself a working mother - said the report exaggerated the effects of the working pattern of the mother.

"That the mother works is far less significant than family income or, for that matter, the education that's available to children," she told BBC Radio 4's Today programme.

"If we are concerned about child development, we would do better to address poverty and improve education," she said.

Mothers returning to work was not a whim or an indulgence but more an economic necessity, she stressed.

Fathers needed to take more responsibility for childcare and there should be more flexibility in the workplace for both parents, she added.

Different generation

The Education Secretary David Blunkett regretted that researchers had not extended the study to comparing the attainment of children of employed and unemployed parents.

Mr Blunkett said there was evidence that children growing up in homes where there was long-term unemployment performed less well at school.

The Social Security Secretary Alistair Darling says that the survey is based on a much lower level of childcare than is available to today's parents.

"The Rowntree study is based on children born almost 30 years ago when there was little quality child care or nursery education and nothing to make work pay or to make work possible.

The report was cited by shadow social security secretary David Willetts, who said that the benefits system should not be used to push both parents back into work.

Necessity

"It shows how wrong the government is to bias the tax and benefits system in favour of two-earner couples and institutionalised childcare.

"We believe that parents with young children should be free to choose whether and when they return to work," he said.

But National Family and Parenting Institute chief executive Mary McLeod urged caution on drawing too many conclusions from a single survey.

"Many aspects of family relationships, and their environment, have a bearing on outcomes for children. For many mothers full-time work is a necessity, not a lifestyle choice. I hope this research won't be used as another stick to beat them."