It is real, at least in one Asian data set, as these new NBER working paper results are brought to us by Zoë Cullen and Ricardo Perez-Truglia:
We use an event study analysis of manager rotation to estimate the causal effect of managers’ gender on their employees’ career progression. We find that when male employees are assigned to male managers, they are promoted faster in the following years than they would have been if they were assigned to female managers. Female employees, on the contrary, have the same career progression regardless of the manager’s gender. These differences in career progression cannot be explained by differences in effort or output. This male-to-male advantage can explain a third of the gender gap in promotions. Moreover, we provide suggestive evidence that these manager effects are due to socialization between male employees and male managers.
There is more to the abstract, including a discussion of the benefits of smoking together. Here is an ungated copy.