I discovered fanfic in 2000 after the first X-Men movie came out. I thought it was this wonderful creative enterprise that my comics-loving, writer-aspiring son would love, so I went looking for some stories for him. Then I got interested in the kind of stories you don't bring home to your 12-year-old. Then I started writing. I write X-Men slash fanfiction, the kind we used to call NC-17 before the MPAA was breathing down our necks. Explicit sex, some disturbing themes.
I'd love to hear how others deal with fandom and their kids, particularly if they are engaged in fannish pursuits that are not appropriate for children. Particularly if they are involved in fandoms that interest children. I'm pretty content with how I've navigated that stormy sea so far, but I'm always looking for suggestions and BTDT advice.