Thought I'd pass this along. Haven't read the whole article yet, but it sounds fascinating.
TL;DR: Looks like contributions by women are accepted *more often* than those by men, but *only *if the project leader doesn't know the pull request is coming from a woman.
Excellent summary: http://arstechnica.com/information-technology/2016/02/data-analysis-of-githu...
Preprint: https://peerj.com/preprints/1733v1/
Note: this work has not yet been peer-reviewed.
J