First, you're correct: I never meant to conduct a meaningful study. It was purely of my own curiousity that I did this. However that does not preclude someone else, of any gender, doing so more scientifically. And to answer your accusation: yes, I did submit the same patch twice, under two differently gendered names (although never publicly, I would copy-paste the patch and privately email it).
Second, my primary source for whether a name is "female- or male- sounding" is historical lists of most popular baby names for each biological sex, found through google searches.
Furthermore, I certainly have bias. Unfortunately, I have so much bias! As someone who, in grade school, was named Charlie, and had the shit beaten out of me for it, I very strongly know how it feels to be a man/boy who doesn't fit the socially-prescribed norms. However, when I am writing patches for code which determines a user's security, I do not play games; I want that code accepted, no matter what. The code submitted as a "female" was usually either rewritten by a certain gnupg developer (often to include further vulnerabilities and UX pitfalls) or later accepted as a "male".
Lastly, if you submit 10-30 patches over a decade, it's not very hard to make the acceptance/rejection rates come out to nice even numbers. I don't think there's anything as high-level as "identity politics" at play here; I'm merely suggesting that there is bias and that all of us, no matter what our gender or how equitable we are, may have it.