“I HAVE 27,481 points on Stack Overflow,” is not something you often see on Instagram, a photo-sharing social-media platform. When Lyndsey Scott, an American model and accomplished software developer, was ridiculed for her programming skills, she referred to the points she has earned solving coding problems on Stack Overflow, a help forum for developers. With over 9.5m members, it is among the 100 most popular websites in the world, attracting more visitors than the New York Times or BBC. But a recent survey of its users highlights a problem. Only 6.9% of respondents said they were female, and if Ms Scott’s experiences are anything to go by, women who code are not made to feel welcome by their peers.

The tech world can feel clubby. The survey found that 40% of women (and nearly 28% of men) feel that they are not part of the Stack Overflow community. Men are more likely to feel they belong than women—unless those women have been coding for 27 years or more. If this is because women are outnumbered, it is unlikely to improve any time soon. The share of bachelor’s degrees in computing awarded to women has halved since 1985, even as the proportion of degrees earned by women in other traditionally male-dominated fields such as maths and engineering has increased.

The spread of online tutorials might help. Among users of Codecademy, a popular online tutorial platform for beginners, about 28% of those who reported their sex said they were female. However, women with coding degrees are less likely to enter the industry and more likely to drop out if they do.  

Men who use Codecademy are almost 55% more likely than women to say that learning to code has helped them make more money. They are also 150% more likely than women to get a promotion after learning how to code. Groups that encourage women to code, such as Girls Who Code and RLadies, offer guidance and women-only work spaces. But making coding less of a boys’ club will not be easy.