Genres and writing

A friend of mine emailed the other day to ask my opinion on this:

I just heard someone say that writing fiction is same in every genre.

Does writing speculative fiction follow the same rules, have the same elements as other forms of fiction. Does writing speculative fiction present different challenges because it is fantasy or science fiction. If so, what are they?

It got me thinking because at its heart, it's true: writing is writing, regardless of genre. But there are differences. I don't write much speculative stuff. It's not what I enjoy reading most of the time.

I think the challenges posed by speculative fiction lie in the world building. In contemporary fiction you can skimp on this because it's set in the real world that we live in. Spec fiction either twists our world to its own needs, or creates a whole new world for the story. So the mechanics of that world and how the societies that live in it work, need to be made clear. But without info-dumping.

I've seen submission guidelines on numerous spec fiction publications say they only want 3rd person past tense narratives. So perhaps that is a genre convention. Although I have seen first person spec fiction done very well. In fact, I just had a piece of mine, written in first person present, accepted for publication in an anthology of apocalyptic tales.

I think that with writing in any genre, you need to have read widely in it so you have a grasp on the conventions. You don't have to go with them, but if you're going to break rules, you need to know what rules you're breaking. But whatever you write, you need engaging characters, an interesting plot, and a unique way of stringing words together to create these things.

What do you think? Is all writing the same when you get down to the nuts and bolts?