Is Kindred really Science fiction?

Do you feel that Kindred should be classified as science fiction or fantasy? A Writer's Digest book I have defines science fiction as "literature involving elements of science and technology as a basis for conflict, or as a setting for a story." Usually, too, science fiction is set in some futuristic world. However, fantasy is usually about a "fanciful, invented world," so Kindred doesn't qualify as pure fantasy either. (The Norton Anthology labels the work "fantasy" in one place [2515] and "science fiction" in another [2135]). Orwell's 1984 is about time travel, too (the reader's, not the narrator's), but the focus is on social problems, not science and technology. Time travel alone doesn't make a book science fiction. Like Orwell's book, Kindred uses time-travel as a pretext for revealing social/political issues. Butler herself classified her novel as "grim fantasy" with "no science in it" ("Reader's Guide" 269); so it is not science fiction, like her other "futuristic novels" with "mutants or extrasolar aliens" (268). Additionally, Kindred contains the supernatural or paranormal: Dana seems to have a sort of telepathy about Rufus's danger which triggers her being transported. Thoughts?