This is a tough subject. A meaty subject. A big ol’ gristly steak of a subject that takes a lot of chewing and will not be thoroughly digested within a single blog post, but let’s dig our teeth in, shall we?
As writers, our characters probably look, act, and live like people we’re used to. If you’re white and straight, your characters are probably white and straight, because that’s what you know, and writing someone black or gay or Muslim or in a wheelchair takes some extra thought.
But here’s a really cool thing: the world is a far more interesting place than just white and straight (and male, and Christian, and able-bodied, etc etc), and there should be stories to reflect that. Because all stories deserve to be told. As citizens of the earth we have a duty to represent more than just our limited bubbles.