In a comment on a previous post about my taste in literature, The Silver Eel asked why I did not list Margaret Atwood. It's a good question, and there's actually quite a good reason why not.
SF (science or speculative fiction) is not just a genre for geeks; it is a serious exploration of what life might be like if you changed one or more parameters of existence, either social, scientific or technological.
Classic examples of the genre include Where late the sweet birds sang by Kate Wilhelm, Always Coming Home by Ursula K Le Guin, Snow Crash by Neal Stephenson and many more; books by authors who understand how the technology or science that they are writing about actually works, and manage to write characters and scenarios convincingly affected by changes in the technology or science.
In order for such books to be credible explorations and extrapolations, the author must understand both the science and the characters, and be familiar with previous SF; it's not enough just to be able to write good characters. This is why The Death of Grass by John Christopher works, and The Road by Cormac McCarthy does not work - in The Death of Grass, the ecological disaster scenario is coherent and convincing, and in The Road, it's not - why are a lot of humans still alive when every other life form has died?
Mainstream authors who write science fiction are frequently unfamiliar with the genre and often do not realise that the idea for their book has been done before, probably more convincingly. So the sheer chutzpah that they exhibit in then denying that what they have written is SF, because they write "literature", is outrageous. For example, both Kazuo Ishiguro and Margaret Atwood have denied that their efforts are science fiction. That's why I call this type of book "strain-meme".
And frankly, I thought Oryx and Crake was a pile of pretentious garbage. The Handmaid's Tale was good, if depressing - but still not really SF.
At least Sir Salman Rushdie does not regard his early novel Grimus as "not SF" (though the publishers apparently denied that it was). He also continued to include elements of magic realism in his subsequent novels.