There is a rule, called The First Rule of Children's Fiction which is "Get rid of the parents". In children's fiction this allows the protagonists to mess about without the usual restraints of parental control, so the scene is either in a boarding school (Messrs Potter, Jennings, Bunter for example), on holiday (Famous Five) or, most wonderfully, eaten by an escaped rhinoceros (James and the Giant Peach ).
Getting rid of one parent in general fiction allows for the wicked stepmother (Cinderella etc.) which allows the protagonist to be oppressed by someone who should be protecting them, thus increasing the desperation of their situation, and the readers' identification with the protagonist.
In spanko fiction removing one parent goes half way to obeying the rule in that there is still a possibility of parental control (and presumably punishment in due course) but allowing a bit of leeway to enable misdeeds to be more feasible. Also there will be added pressure on the left-behind parent allowing both for discipline being allowed to slip and also for parental angst which the child protagonist can feel vicariously, thus making them feel even worse when they disobey the poor single parent.
And, yes, I have done it too. (The Tale of Gillian, Sally & Jane go Shopping, Never Too Old) Actually, looking at that list it seems as if there is a theme |