Superheroes: Are They Scifi?

I am a huge fan of superheroes. I love the Marvel universe, and the DC one does some good things too, but is it really science fiction related?

I love the television show Heroes, and would like to talk about it on this site, but I worry that while it appeals to a similar audience, it isn't real science fiction. Sci-fi has robots, aliens, space ships, laser beams, and other such things, right?

Well, what about the fact that shows like Heroes are being held in an alternate reality, where super powers exist. (No, I don't want to fight about the existence or non-existence of super powers in the real world that we live in.) So couldn't we put all superheroes under the category of alternate reality, and thus be included in the science fiction genre?

If you think superheroes would make a good addition to AltSciFi, please let me know, as I'd love to talk about Heroes, as well as some "who would win" reports. (Magneto is the best!)