When you think of someone who is an engineer, do you imagine a man or a woman wearing a hardhat? How about when you imagine a teacher standing in front of a class of schoolchildren? If you answer “a man” to the first question, and “a woman” to the second, there’s probably a reason. And the reason is simply that more men than women pursue careers in fields such as science, technology, engineering and mathematics, while women are over-represented in the humanities and medical sciences. This type of gender segregation in the labour market is still prevalent in many countries. But will it continue? Girls now do as well as, and often better than, boys in most core school subjects; and proficiency in a subject influences 15-year-olds’ thinking about the kind of career they want to pursue. Or does it?