Gender stereotypes and a lack of confidence are putting girls off maths and science, according to an international study.
Even when young women are good at these subjects at school they are unlikely to pursue careers in these fields, it suggests.
The report by the Organisation for Economic Co-operation and Development (OECD) argues that important social and emotional factors affect pupil’s choices, and warns parents, teachers and employers all have ingrained “biases” that they are passing on to youngsters.
The study used data from international “Pisa” tests in reading, maths and science to examine the gender differences in education.
It found that while many countries have made significant progress in closing the gap in many areas, there are new ones opening up, with young men much more likely to have low levels of skills and academic achievement, which makes them more likely to leave school early.
Across the 64 nations examined, women are much less likely to consider careers in science and maths-based subjects and to have the same self-confidence as boys in these areas.
Overall, fewer than one in 20 girls considers working in science, technology, engineering and maths (Stem), compared to one in five boys, despite the sexes achieving similar results in international science tests. In the UK, boys still have a significant advantage in science, far outperforming girls in the Pisa test compared to many other countries.
Andreas Schleicher, of the OECD, said that boys tend to be much more confident than girls, which is a predictor of what they will do later in life.
“If schools succeed in giving boys and girls equal levels of confidence, we would no longer see gender gaps in learning outcomes,” he said.
Girls are more likely to be anxious about maths, Mr Schleicher said.
The report shows that around 65 per cent of girls are likely to worry that they will find maths classes difficult, compared to just over half of boys, and similar proportions say they worry that they will get bad marks in the subject.
It also reveals that in the UK, the link between self-belief and science scores is more pronounced than in any other country apart from New Zealand.
In general, girls, even those that are high-achieving, tend to under-perform when they are asked to “think like scientists”.
These gaps in self-belief can have a lasting impact, the OECD suggested.
Mr Schleicher said the decisions that girls make at school can affect their pay and job prospects later in life.
“At age 15 you have made important choices that are very, very difficult to change, particularly in the Stem areas.”