Your link defines mundane sci-fi as (emphasis mine):
stories set on or near the Earth, with a believable use of technology and science as it exists at the time the story is written.
I don't thing Gattaca qualifies.
As to X-Men, I don't consider them sci-fi at all, at least any more than, say, Twilight.
OK, think Gravity vs. Star Trek (ignoring for the sake of argument the factual inaccuracies in Gravity).
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