Interestingly, although the event description clearly asks: "Are you a woman interested in starting a startup?", if you click through to the application, it actually asks you for your gender. Is that because YC would still like to know now many men want to be present at the event? Is it because men are allowed, but they're not advertising it? Or will they simply inform all men that applied that regretfully their applications have been denied?
And for trans people who don't conform to the gender binary, no option whatsoever: there's only "male" and "female" as an option. Now, I'm not asking for that crazy xe and xir stuff, but if you're going to go to a conference where their main claim to fame is being gender themed, you should be able to put down "other" or "prefer not to specify" (the latter of which may be preferred even by some people who are firmly on one end of the gender spectrum). One big problem I have with events that are either thematically or exclusively gender segregated is that all it really does is reinforce gender roles. You've got to pitch in with one camp or the other, so that the privilege checkers know how many points to assign you. I don't like it. My computer doesn't care what my gender is or isn't, or what's between my legs. That's actually one--of many--things that has drawn me to tech.
Yes, particularly relevant in the Bay Area, where gender discussions are mainstream. I lived in the student co-op system in Berkeley, and it was then for the first time that I really started to appreciate the meaning of "other" as a gender option. I guess YC and SV companies are not yet ready to be that "open-minded"?