Do guys write fan fiction?

I'm just curious, because I've never come across a fan fiction written by a guy. Do they write it and I'm just not reading the right stories or is it more of a girl thing? And if guys do write fan fiction, what sort of stuff do they write? I've been curious about this for a while now, so if you are a guy and write fan fiction, tell me please. And also, if you've ever read any good fanfictions written by a guy, could you put the link in your answer? Thanks!