I asked these and similar questions to authors I met at the Kindling Words conference and noticed that a number of authors had decided, after struggling with this question, to write their book from a Caucasian character's point of view. Even if the story and theme were about the other group, they created a character who filtered the story through their own Caucasian experience.
There were a few reasons for this, but the biggest was that the authors were afraid of receiving criticism for co-opting a story from a group they did not belong to. And while it's true that some outspoken individuals believe that no one can represent a group they don't have firsthand knowledge of, they underestimate the power of imaginative empathy and the mighty strength of good research.
And they also seem to forget a most important point: no one is asking the author to represent an entire group of people. We are asking them to present one person's story. Almost because there is so little available about some people, we expect every story to be THE representative story and not just A story.
Unfortunately, this fear of criticism, coupled with a disproportionately large percentage of white published authors, results in a publishing landscape where too many people of color are relegated to secondary-character roles.
So. As you may know, I do not agree that any one group of people has more of a right to tell a story than another. I do not believe in looking at the author's name before judging the quality of a book (and even if I did, what would that tell me, in this day and age?). I urge authors to write on whatever subjects most move you, and from the point of view that most moves you. Don't be cowed by the small-minded and exclusionary among us. When they twitter and post diatribes on the blogs, don't worry. We of the broad mind and love of the good story will be here to cover your back.