Your child is a human being! A cool one! Because this human being is building an infrastructure for critical reasoning in a frequently bizarre, paradoxical universe where fairly miraculous and fucked-up stuff happens on a regular basis. Of course adolescents have an irresistible attraction to adult themes; perverse and puritanical an instinct as there is in this culture to prolong childhood, there is a far stronger counter-instinct in children to analyze, simulate, and as soon as humanly possibleparticipate in the challenges of adulthood. This is not to suggest that growing up is a process that should be unnaturally accelerated, or that it can be in the first place. These days, casual observation suggests that in a modern urban environment, childhood is a stage that lasts approximately 30 years. But we should be counted lucky when this fascination with the adult world manifests in wanting to read more books.
Basically, he argues that children should not be shielded from difficult reads at a young age. I would further that and carry his advice to music, movies, etc. Kids can handle more than parents want to believe.
Most of the books that rocked my world as a teenager were all “adult” fiction.