As nearly always, this post is a crosspost from a response to a poster over at Absolute Write.
The poster, named "showtimecircus" asked if any of us felt guilty about writing outside their chosen genre. My response follows,
Showtime, Nope. Write what you want and need to write. Write what comes to you and how it comes to you. The muse is too fickle to not be listened to and the more you refuse to listen to her, no matter what genre she's telling you to write in, the less often youre going to hear from her.
Plus, writing (and reading) outside your genre is inevitably going to lead you to introduce some different elements into your writing. It's going to help build you as a writer and to introduce you to new elements of your creativity and writing ability. Introducing new elements into an old genre is practically the definition of "published writer". Too damned many people try to imitate this writer or that writer to the extent that they forget that this writer or that writer got themselves published by trying something new and different.
There's nothing wrong with introducing elements of detective fiction into science fiction (Glen Cook does it in fantasy). There's nothing wrong with introducing elements of science fiction into a thriller (Jon Land, Timothy Zahn, and Dean Koontz). There's nothing wrong with introducing elements of fantasy into police procedurals (Fred Saberhagen did it with An Old Friend of the Family and Dean Koontz did it with his Frankenstein series).
Reading Dashell Hammett and Raymond Chandler and Glen Cook lead me down a road to the creation of one of my favorite characters who happens to be a pretty hard-boiled private investigator who just happens to attract weird.
Do what you want to do. There are no rules and no binders saying you must write only in one genre (James D MacDonald writes in several just to name one example who lives here at AW).
Break the rules. Do it with originality and talent and the next thing you know we may be talking about you as a "published writer".