**New working paper** How does the under-representation of females in Economics affect the career trajectory of female Ph.D. students? Sahar Parsa and I look at this in a new working paper by exploring sabbatical leaves taken by female professors at top-50 US Econ departments.

We study the effect of female professors' sabbaticals using a novel dataset on close to all 1998-2015 advisors-advisee relationships and early-career outcomes of top-50 PhD students. Here are our 3 main results ⬇️

1. Female PhD students in their 3rd year at the time a female prof goes on leave publish much less in the five years after getting their PhD, declining 33% relative to the sample mean.

2. The fall in publications of female students is matched with a fall in the probability of being placed in academia of 9.8%-points (20% of the sample mean).

3. For male students, we find what looks like a zero-sum game: affected males publish more and are more likely to stay in academia.

Still, placements are not of equal “quality". Females are missing from the top-ranked institutions, while males fill lower ranked positions.

What explains these results? We argue that the effects are connected to gender homophily in professional and social networks. The absence of female mentors hinders the development and placement of female students, while indirectly benefiting male students (perhaps through reduced competition).

To support this interpretation, we – among other things – provide evidence of gender homophily in advisor-advisee relationships. Even controlling for department-year-field fixed effects, we find that female students are 50% more likely to have a female advisor compared to male students.

How does it all matter? Our findings underscore the importance of same-gender mentorship in male-dominated fields like Econ. A counterfactual exercise suggests that hiring one extra female prof at each of the top-50 schools would close 1/3 of the gender gap among ass profs at the top-25 schools.