This paper examines the relationship between gender diversity and the diversification of ideas in Academia and in the knowledge sector. Diversity in employee representation is often advocated for its potential to foster diversity in ideas, and thereby innovation. However, this process of ‘diversifying ideas’ critically depends on decisions of incumbents, such as hiring and funding. If interests and ideas differ between incumbents and minorities, it may be difficult for minorities to ‘break through’. We first present evidence from the Academic Economics junior job market, where numerous initiatives have been launched in recent years to boost the representation of women. We find that women fare as well as men on the market, but they fare substantially better if they specialize in a more male-dominated field. In an Online Experiment, we study the demand for ideas in a college-educated population. We find large gender differences in the topics men and women choose to engage with. We then show that incentives encouraging the selection of topics that are typically more female are more effective at increasing their representation than incentives encouraging the selection of women.