But when Riegle-Crumb controlled for those and other possibilities, she found one reason remained: “What we found is that in communities that had a higher percentage of women in the labor force who are working in science, technology, engineering and math, that in those schools, girls were as likely as boys to take physics, or even more likely.”

Riegle-Crumb’s finding about the importance of local role models meshes with a broad range of that shows the decision to pursue math and science is not about innate differences between boys and girls, but about and norms. Countries with greater , for example, reveal more equal math test scores among boys and girls.

Teenage girls growing up in communities where women are better represented in tech are more likely to see women commenting on tech issues in public forums and in school discussions — and more likely to run into a friend’s astrophysicist mom at a birthday party.