Of the many nerd things I'm glad not to have experienced, assuming I'm "faking it" because I'm a woman is currently at the top of the heap. It's still a bewildering thing to see happening: some people are convinced there is a vast co-option of geek culture through feminine fakery, and it must be stopped.
Beautiful women are apparently just salivating at their chance to dress up in sexy cosplay for the sole purpose of having stunned man-geeks bow at their feet. They have no interest in the material, just come for the worship. Or some girls call themselves "nerds" when they don't do enough nerdy stuff to earn the title. It's the old "true fan" argument, now with bonus misogyny.
Such stories sound like the judgement of complete strangers, or purple-monkey-dishwasher anecdotes that come from a deathly fear of girls getting into the treehouse. Yes, there are female models that companies hire to promote their stuff without knowing about the property, but this isn't about that. It's about female cosplayers who happen to be attractive, and are simply assumed to be there for attention. Man-geeks must think really highly of themselves if they believe women have nothing better to do but put time and effort into their costumes and pay to go to conventions, just to be She Who Must Be Obeyed to all the poor, put-down man-geeks.
The second thing, of assuming that women who call themselves "nerds" just haven't earned it—come on. I guess all those words putting down the "true fan" mentality still fall on deaf ears, or maybe they believe there is an exception when we're talking about overall geekdom rather than a specific fandom. Either way, it's bullshit. You don't need to follow a doctrine to be a geek. You don't have to know everything, collect everything, do everything. And you especially don't need someone else determining how best for you to defined yourself.
I'm also stunned when the question of why nerds need "cred" is answered by saying that these "posers" haven't suffered the social ostracism, the Indiana-Jones like quest to find nerdy material, or whatever "hardships" defined the nerdy life of yore. But having obstacles between yourself and your hobbies doesn't say anything about your righteousness. All of it's just materialistic acquisition, and there's nothing moral about having to fight for your trinkets.
There's also an assumption that "fake geek girls" are doing it to claim a place in a "popular" subculture, one which is just so gosh damn desirable they want to pretend their way into it. Again, it's this bizarre arrogance, assuming people would spend all that time and money for the sole purpose of getting attention from them.
What you get from all this is that women are apparently hungry for male attention, those crazy harpies, and will modify their lives in any way to get to that sweet, sweet man-ness. It's never thought that they might want to do something for themselves, and they might even do it a different way than the "proper" geek channels.
Where does this idea come from? It's partly the strange protectiveness that subcultures get, the sensation that they are apart from the world because their interests are special rather than uncommon. There has been so much material framing geekdom as a male-only thing, it's easy to imagine a unique wariness when women and girls enter geek space, because they might not be "special" enough.
That's not to mention the larger assumption that women aren't supposed to let hobbies define their lives, that women are the mothers who tell you that you're too old for toys, and the girlfriends who don't want to play RPGs. The sitcom fantasy of women being the ones who stand in the way of fun and fantasy leads to the assumption that women must be entering geek space for an ulterior motive.
Yeah. But these aren't excuses. They say it's just a "certain kind" of women doing it. But it's always a woman. Always. That tells you something, doesn't it? There is no reason not to give the benefit of the doubt to someone entering your hobby space just because of their gender.