Why are there so many orphans in literature?

Are orphan stories a relic of our grim past, or are orphans just a convenient plot device?

The Tale of Desperaux: In Which I Am a Crying Fangirl

Two weeks ago, I had the great honor of meeting Kate DiCamillo. After hearing her talk, I stood in a long line of nine-year-olds, heart palpitating, to have her sign my copy of The Tale of Desperaux. When I got to the front of the line, and Kate DiCamillo said, "Hello! How are you?" I almost …