Teenagers who attend single-sex schools do no better in exams than those in co-ed schools, according to research published today. But they are twice as likely to study subjects not traditionally associated with their gender.

Researchers from the Institute of Education in London found that 22 per cent of pupils in all-girls’ schools gained maths, chemistry or physics A-levels, nearly twice as many as in co-ed schools. Boys in single-sex schools were similarly more likely to take English and modern language A-levels.

The findings come from a long-term study on the lives of nearly 13,000 people who were teenagers in 1974 and are now in their 40s.

The study found pupils in single-sex schools were also more confident in their ability to do well in these subjects and girls were more likely to gain qualifications in male-dominated subjects at university and go on to earn higher salaries.

But the research, which was funded by the Economic and Social Research Council, shows single-sex education made almost no difference to exam results.

Boys did no better once their family background and previous ability were taken into account. Girls did fractionally better at O-level than girls in mixed schools, but did no better in further and higher education.

Alice Sullivan, one of the researchers, said: “Our study emphatically does not support the suggestion that achievement is higher in single-sex schools.”

However, Dr Sullivan said that such schools were better at encouraging pupils to pursue academic paths according to their talents, rather than gender.

“Co-educational schools need to examine the ways in which they have, probably unwittingly, enforced powerful gender stereotypes on both girls and boys,” she said.

The study also found that pupils in boys’ schools were more likely to dislike being there than those in co-ed schools and that both sexes were less likely to truant in single-sex schools.

Single-sex education seemed to have no impact on the likelihood of marriage or child-bearing, or the happiness of their relationships, although men who attended all-boys’ schools were more likely to be divorced by the age of 42.

The take-up of maths and science among girls has increased since the 1970s when the surveyed adults attended school. A study published this summer by Professor Alan Smithers of Buckingham university showed that girls were still more likely to opt for maths and science at A-level if educated at girls’ rather than a co-ed school, but only by a small amount.

Single-sex schools: non technical report is at www.cis.ioe.ac.uk