Reverse-discrimination against men? Rejected, per the observation that there is evidence of discrimination against women when gender is identified.
The most likely candidate of what really happens, given that this benefits the SJW crowd the least. This is especially so when developers are intimidated when they don't follow the politically correct narrative.
- Women take fewer risks, and thus are more likely to provide solutions that are accepted? The authors cite a study that claims women are, on average, more risk-averse than men. However, this is inconsistent with the observation that women change more lines of code.
- Women in open-source are more competent than men? This is the hypothesis that the authors support the most. They suggest it somes about due to survivorship bias and/or self-selection and/or higher implicit performance-standards in the female population of open-source coders.
Not as likely given that they're more in line with attempts to fit the data to the hypothesis.