Sci-fi seems to mean 'anything that looks vaguely technical in a story'.<p>SF, especially, hard SF, has always tackled grown up questions.<p>Here are a few I have recently re-read:<p>The Dispossessed by Ursula K. Le Guin,
Saturn's Children by Charles Stross,
Engines Of Light by Ken McLeod,
2001 by Arthur C. Clarke,
Robots of Dawn, etc. by Isaac Asimov.