Maths is the most popular subject taken at A Level in the UK. Most of the best-paid jobs are in the technology and finance sectors, which tend to require maths. The majority of students achieving the best grades in maths are boys, which helps to explain the persistence of the gender pay disparity. But what explains the gender disparity in Maths A Level results – genetic inheritance or social conditioning? International studies of achievement in maths show that in some countries girls outperform boys in maths, suggesting that social conditioning is the explanation. From this we can conclude that the better achievement in maths of boys in the UK is caused by low expectations of girls in maths by teachers and parents.