It's sci-fi. Most hardcore sci-fi fans are thought of as social outcast weirdos.
Also, some Star Wars fans do this, which is essentially cosplaying:
As for Doctor Who: any fan I've known has been a social outcasted weirdo.
Again, this depends which definition you go by.
If I go by "nerd" being studious and smart, then liking fictional franchises has nothing to do with either of those. The scientific aspects of it aren't realistic at all.
You can discuss flamingly gay men in a separate thread.
Again, when I read the descriptions of those... at least 90% of the people I know fall under one of those if not both. I don't get how those could be actual disgnoses; nearly everyone has them. The point of a diagnosis is to point out something abnormal, usually.
Aww did I butthurt you? :3