Our results show that women’s contributions tend to be accepted more often than men’s [when their gender is hidden]. However, when a woman’s gender is identifiable, they are rejected more often. Our results suggest that although women on GitHub may be more competent overall, bias against them exists nonetheless.
…or the research is flawed. Gender identity was gained from social media accounts. So maybe it’s a general bias against social media users (half joking).
I think (unless I misunderstood the paper), they only included people who had a Google+ profile with a gender specified in the study at all (this is from 2016 when Google were still trying to make Google+ a thing).