Depends. Tolkien, for example, bound himself pretty tightly to his pre-designed fantasy universe (which he designed to fit in a bunch of fantasy languages he had come up with. Linguists are such geeks).
Your mileage may vary, but I find his storytelling isn't as strong as his world crafting.
J.K. Rowling, on the other hand, didn't pre-define much of her universe, which suits her more flexible writing style, but leaves a sizable amount of inconsistencies in the Harry Potter series.
So yeah, fantasy is like any other genre, only that you use the word
magic where you'd use the word
science. A lot.
moi said:And yes a genre is always about something but I won't debate this
I would debate, but the
Wikipedia article has a very comprehensive explanation, with plenty of references. Bolded bits for your pleasure:
Genre is the term for any category of literature or other forms of art or entertainment, e.g. music, whether written or spoken, audial or visual, based on some set of stylistic criteria. Genres are formed by conventions that change over time as new genres are invented and the use of old ones are discontinued.
Mind you, I'm not saying you are wrong in your definition, but rather that it isn't being applied to the right scope.
For example, while Sci-Fi encompasses any and all stories with the faintest of scientifical/technological elements, if you were to refine the definition, to, for example,
science-fiction procedural action romance, then you'd be right, under such tighter definition, stories that fall under said label have to be about something specific.
In other words, genre is a bitch to define. As the Wiki article points out, there's been plenty of discussion on the subject, including this little gem:
The phrase "tyranny of genre" comes from genre theorist Richard Coe, who wrote that "the 'tyranny of genre' is normally taken to signify how generic structures constrain individual creativity" (Coe 188). If genre functions as a taxonomic classification system, it could constrain individual creativity, since "the presence of many of the conventional features of a genre will allow a strong genre identification; the presence of fewer features, or the presence of features of other genres, will result in a weak or ambiguous genre identification"