Have you noticed that people who aren't into science fiction refer to it as 'sci fi', but a growing number of SF fans are proclaiming that they don't like the phrase? They like to use the full term 'science fiction', or to say 'SF' because it could also stand for 'speculative fiction'.
Personally I don't see the problem. I mean, 'science fiction' never was a great term to start with. We don't write fiction about science, we don't even necessarily write about fictional science; but we all know what we mean.
So, there we have it: I write science fiction stories and other tales with a speculative element. I'm a sci fi author.