I certainly don't look like a stereotypical nerd (female, tall, fit, well-dressed). It's actually quite a disadvantage in a way. I'm exposed to a lot of instances where I meet another female, we get along well enough, and inevitably the conversation turns to interests - and most women will be taken off-guard by my "weird" hobbies and there'll be a very obvious uncomfortable moment when they decide that all of a sudden I don't live on their plane of existence and now we have nothing more to talk about. Sometimes they'll say something like, "oh, yeah, my brother likes that stuff...", but you can tell they just feel awkward. And then we never speak again.
In summary, I'm pretty alienated from most of my gender, but because of my appearance it takes them a while to realise it. It can get disheartening.