There's a great essay by Philip K. Dick (an excellent and important writer whom our reading list kind of grazes) about the purpose and meaning to be found in science fiction. He doesn't directly tackle issues of race and gender, but his interpretations of the purpose of science fiction are fascinating and complex.

Some interesting subjects touched on in this essay: Disneyland and "fake fakes", universes that DO fall apart, and poor translations of his novels. The main thrust of his argument is that science fiction is passed off as patently, unabashedly spurious, and yet there's some parallel way in which many of the things in science fiction are true - sometimes in ways the author could never have predicted. In some ways, he sees a more complex picture than the idea of science fiction as thinly-veiled political writing, which we've already covered as the blanket interpretation of the genre. Though, honestly, as the essay progresses, it becomes more and more clear what a disturbed person Philip K. Dick is, but his persistent wit makes it worth checking out anyway.

Read How to Build a Universe That Doesn't Fall Apart Two Days Later". It'll probably take you less than an hour and it's fascinating.