A number of these assumptions come to mind. For example, many of my poems, at least in their initial incarnations, contain male protagonists. I do not do this deliberately; it stems from the fact that much of my work contains several grains of autobiography, and many of the 'characters' that formed the backdrop of my childhood were male. But I have had to work to ensure that female protagonists and characters get an equal billing. Indeed, this has even inspired a poem on this very theme, 'Henrietta The Eighth', included at the end of this blog post.
I can think of many instances in which I have taken an aspect of my own upbringing and unthinkingly assumed that it applies to everyone else. Further examples include referring to the place one lives as a 'house', and assuming that everyone comes from a cosy, nuclear family. Both of these assumptions are challenged in this poem. Further examples include the assumptions of heteronormativity and gender binarism. . At any rate, I suppose at this point I have only to make the perhaps banal statement that diversity needs to be accounted for both in terms of classroom discourse and in terms of poetry (at least if you are in any way concerned that your poems speak to a wide number of real children). One needs to be alive to the diverse realities of children's lives, and to build this as much as possible into one's approach. Were I to run the 'toys' lesson again, I would thus probably say something like 'make a list of toys or childhood objects'. And were I to write 'Henrietta The Eighth' again perhaps I would go with a transgender, polyamourous monarch.