An interesting article about the idea of the babysitter, in fiction and life:
Teen-age girls have been contesting traditional gender ideals in highly visible ways since the nineteen-twenties. The babysitter has conveniently served as a lightning rod for adults' uncertainties about what the limits of girls' autonomy and empowerment should be. These uncertainties have played out in the media: for instance, unease about the influence of feminism, the sexual revolution, and the counter culture on girls' behavior in the nineteen-sixties led to depictions of delirious babysitters who endangered children and slutty sitters who destabilized marriages in soft-core-porn novels. In the nineteen-seventies, maniacs in horror movies like "Halloween" and "When a Stranger Calls" sought vengeance on teen-age girls unwilling to curb their pursuit of personal independence. In the eighties, it was the babysitters themselves who turned murderous in made-for-TV movies, a fantasy created, perhaps, in response to girls' uninterrupted determination to achieve authority and self-sufficiency.