When you tell people you write fiction, an awful lot of them nod and smile, thinking that means you're in the entertainment business. Well, yes, that too... but for many of us, fiction is about a whole lot more than just telling a good story. It's about examining truths, and pulling forth stories which help us think about issues and, hopefully, in the end understand a bit more about who we are--as a species, as races, as genders, as individuals.
When you say you write science fiction, the smile often takes on a sort of frozen look. Science fiction, how nice. (Unless you are talking to a sci-fi fan, in which case you are assaulted with questions about your books or stories). Good science fiction is about the same things as regular fiction, only perhaps a bit more self-consciously. Take Ursula Le Guin's "The Left Hand of Darkness." She is able to examine sexuality in a way standard fiction can't because of the society/species she creates. Or Orwells 1984, which examines governmental thought control and totalitarianism in a way that wouldn't be very possible in straight fiction, because (one hopes) the extreme version he writes about would never be tolerated in the real world.
Science fiction writers (at least my favorite ones) focus and crystalize an issue, capturing the essence of it, intensifying it, removing the noise and distraction and messiness of real life, so they can pick it apart. It results, often, in a very intense experience, that can have a significant impact on the way you see your world, your life, your relationships.
The Boston Globe a couple days ago ran an article talking about the roke of science fiction, particularly utopias and dystopias.http://www.boston.com/news/globe/ideas/articles/2005/11/20/back_to_utopia/?page=full
"The authors says about one book: ''The Three Stigmata of Palmer Eldritch" (1965) is a psychedelic odyssey of hallucinations-within-hallucinations from which no reader emerges unscathed."
Yes, that's the idea -- many authors of sci-fi hope the reader will come out on the other side of their book changed, or at least at bit more thoughtful.