Women are severely marginalized in software development, especially in open
source. In this article we argue that disadvantage is more due to gendered
behavior than to categorical discrimination: women are at a disadvantage
because of what they do, rather than because of who they are. Using data on
entire careers of users from GitHub.com, we develop a measure to capture the
gendered pattern of behavior: We use a random forest prediction of being female
(as opposed to being male) by behavioral choices in the level of activity,
specialization in programming languages, and choice of partners. We test
differences in success and survival along both categorical gender and the
gendered pattern of behavior. We find that 84.5% of women's disadvantage
(compared to men) in success and 34.8% of their disadvantage in survival are
due to the female pattern of their behavior. Men are also disadvantaged along
their interquartile range of the female pattern of their behavior, and users
who don't reveal their gender suffer an even more drastic disadvantage in
survival probability. Moreover, we do not see evidence for any reduction of
these inequalities in time. Our findings are robust to noise in gender
recognition, and to taking into account particular programming languages, or
decision tree classes of gendered behavior. Our results suggest that fighting
categorical gender discrimination will have a limited impact on gender
inequalities in open source software development, and that gender hiding is not
a viable strategy for women