As the sole criterion, this doesn't seem a fair way to determine the status of which books are Christian fiction and which are not. In fact, I'm certain that this is shorthand used by the bookstore employee to say something different, something that has to less to do with "Christian fiction" than it appears.
If you start listing the authors who are Christian but are considered "mainstream" it's a pretty interesting list: Wendell Berry, Marilynne Robinson, Flannery O'Connor, Victor Hugo, Fyodor Dostoevsky, Graham Greene and Leif Enger would all be on this list. All of these authors have overt Christian themes in their books, with Christian characters (including priests, pastors and so on). They are all exceptional writers, so it could be that their work has "transcended" the title of Christian fiction.
|And then the Lord God smote Borders
for shelving the Bible in the "fiction" section.
We see this in other genres defined by status, identity or affinity group. Women's fiction is not for men. "Asian-american fiction" is about the Asian-American experience and isn't "universal." Pretty much any time someone attaches an adjective to the term "fiction" that is not directly related to genre, what they're saying is, "This book is for someone other than me." Or, in the best case scenario, it can be used within that community to say "here are books about us and the things that matter to us."
All that to say, when people outside the Christian community call something "Christian fiction" what they mean is, this book is not about my life. It doesn't intersect with my needs, concerns or life. That's tragic, because the deepest idea of the good news about Jesus should be that it has something to say to every human being on earth.
Now, for some people that's going to be okay. There are Christian authors whose primary audience is and will continue to be only Christians. But it seems to me that at least some of our work should be of central value to the lives of those outside the Christian community.
So, what do you think? What examples would you give of "Christian fiction" that would be good for people who aren't Christians? What are some ideas of what fiction by Christians should involve/include/be about to be of use and interest on a universal rather than narrow scale?