To followup, I suppose we are typing fiction based on the the "what if" aspect of the story. Star wars "what if" is the force. That is so very indistinguishable from magic that the stories are fantasy stories, no matter that the society is depicted as futuristic. Star Trek is all over the place. Transporter accidents are more fantasy what-ifs. Alien symbiotes (Trills) which enable personality to preserve over generations seems more science fiction. Stories that look at the question of how a technically advanced society interacts with a less advanced society, I'm not sure about, since there are historic examples, but the underlying theme is based on technology, which seems footed in science fiction.
In other areas, we could have a "what if" of a physicist who gains superpowers when angered (the Hulk, then Supers as the fiction domain, with an odd fit to both fantasy and science fiction).
That is not to say, this is the only way to present the question. Equally, we could look to how the "what if" element is handled in the story, say, a fantasy element which is subjected to scientific rules (or not).
Thx!
TomB