Here, free to a good home, is a possible study for literary sociology: an analysis of writers who wrote "evil child" fiction, and how old their oldest child was when the stories and books were written. You know the kind: beautiful, normal-seeming child either suddenly turns evil, or is revealed to be evil all along. People are impaled, other children tortured. The world might even be at risk?
My hypothesis? Their oldest child had just reached adolescence. Your nice, sweet, adorable offspring is suddenly demanding, angry, duplicitous, independent, and utterly irritating. For a writer, life isn't just life, it's material. You can channel your despair ("this is the result of evil forces beyond my control") while simultaneously giving a sort of comfort ("it's not your fault").
Most writers are really pretty lazy, so domestic situations are a natural. You don't even have to get up from the kitchen table (except maybe to pick your demon-possessed offspring up from the police station).
Of course, I am much too lazy to back this up with serious statistical research. But if someone is looking for a thesis topic in modern competitive academia and want to do it using a kind of literature you already read for fun, this might be a good one.
Just mention me in your acknowledgements.