Half the struggle is in getting kids to write anything creative at all. I did a project looking at different ways to prompt and develop storytelling with 14 year olds, and some of them were as watertight as granite when it came to getting them to exercise the rainbow (as opposed to grey) matter. However, given enough encouragement it was surprising how the most uptight, grade-grubbing nerdy kids would let fly with some mad storytelling (one very scary one about zombies springs to mind). Alas, so much of school now seems to be utilitarian, and its surprising just how many kids are quite happy about that! If only they knew that all that learning how to write business letters will have been useless when they get jobs and have to conform to the corporate house style...
What I don't like is that children are being encouraged not to write on certain subjects, as you will write about whatever turns you on, frankly! Yes, learn different styles and formats of writing, but as for whether you write about pixies, ponies, politicians or pugilists, it's
your voice. Where i can see that this comes up as an issue is when you get that kid who sits there wailing "But I dunno what to write about!" The easy way out then is to say "Write about what you know!" However, the kid who
knows what they are going to write about is a treasure! And that makes me think of my old writing tutor - I'd spend hours gassing away to him because I had a ton of ideas, but he used to get exasperated at the number of students who'd opted to take a degree where writing was compulsory and could come up with nothing more unique than rhetorical and repetitive verse about why people die in Africa. Also he liked to see what wacky outfits I'd turn up in - the vintage velvet bellbottoms were a fave I recall, but I digress...
Luckily I had good teachers more or less, laying aside the alcoholic who told me I'd fail my O Levels (riiiight, brain addled by vodka....) so nobody told me what to write about, just how to do it. And they had trouble stopping me at times. I think that's why I like Lyra in HDM so much - she's full of stories.
But there is one lesson that's a good one to learn, and that's not to stick within genre cliches - in fact forget all about genre and whether what you write is realistic or fantasy or not - just write what's swirling round in your head if you want to be really original