Hey, I am a Freelance writer, former journalist, and presently have a fiction novel being placed with my lit agent; the novel isn't Sci-fi, but there is all types of sexuality. Anyway, I think Science Fiction lends itself to "putting itself out there," so I really wouldn't worry about it not being well recieved.
One important thing to consider, however, is who your target audience is? Will general sci-fi fans eat it up, or will it be more of a cult readership? Is the book more literary in nature, or motivated by action?
A great place to begin getting a clearer picture is to write a rough draft of your book proposal; it's what you will have to submit to a lit agent with your manuscript. You have to anwser questions that may help at this step in the game. Google Book Proposals, lots of great formats & examples.