We as writers often argue that genre is a marketing tool. I've made that case here before in so many words. How else do people find books in the store? Just like having a space ship in the cover art signals "science fiction" to the bookstore browser, so does the little word "Science Fiction" printed on the spine. Spaceships on the cover of a hard boiled 1940s Hollywood murder mystery would be misleading at best, unless there was a very specific plot element in play.
However, during the writing process, the author's conscious choice of genre can be important. Critically so, I'm starting to believe. (This is a new line of thought for me, so bear with me.) The example case is one specficrider and I raise in our February article (no link yet).
By the same token, when literary writers adopt science fictional language, while still employing their core emotional tropes, the result is often oddly unsatisfying to genre readers. Kirstin Bakis' Lives of the Monster Dogs (1997), Audrey Niffenegger's The Time Traveler's Wife (2003), and Michel Faber's Under the Skin (2000) are examples of this trend.
I'm not going to steal further thunder from the article right now in this forum, but I will put up a link as soon as it's available. However, I find it interesting that this seems to be a clear case where authorial intent matters considerably. Imagine a non-genre writer addressing a generation ship story, for example. If they are not an experienced genre reader, they won't be familiar with the tropes of FTL and sublight travel, Mayflies and For the World Is Hollow and I Have Touched the Sky, and so forth. However they choose to address generation ship issues, the writer is quite likely going to violate the expectations of a genre reader, which are based on a long-running conversation in the field around the trope of generation ships.
Does that count? Does that matter? karindira thinks it arrogant of SF to claim ownership of such topics as time travel, genetic engineering and generation ships. Yet this is an established literary and even cultural tradition, with a body of thought and experience. As I pointed out to her, some of our reactions to outside (ie, non-SF) writers using our tropes amount to professional jealousy -- when *I* write about post-apocalyptic religious cults, I'm dismissed as a mere genre writer1, but when Margaret Atwood does the very same thing, she's lauded in the press and academe as an innovative literary figure.
Like I've said before, millions of people who wouldn't touch that science fiction trash read that nice Mr. Crichton's book about cloned dinosaurs. Oh, the irony.
1 A theoretical example. I've not yet written a post-apocalyptic novel, nor have I yet been excoriated in the press. I figure if I stick around long enough, both of these things may happen.