Finding Nemo, fables, and family values

Seeing Finding Nemo this weekend reminded me of the fairy tale trope of the parent-less hero or heroine, as if having parents disqualifies one from taking the archetypal heroic journey. Sometimes the hero is missing both parents; evil or dislikeable stepparents or foster parents are optional add-ons (Cinderella, Sleeping Beauty, Lion King). Sometimes one parent is missing; this is the so-called single parent fable household, though sometimes the single parent remarries, though rarely to someone as kind as the person they're replacing (Nemo, Hansel and Gretel, Belle, Pinocchio). Often these heroes grow up in the company of a motley crew of friends, including anthropomorphic animals and household objects or dwarves (Belle, Cinderella, Tarzan, Snow White).
But we know that in society, generally kids who don't have any parents or just one parent are susceptible to a higher rate of social problems. I don't have the statistics handy, but in my experience, kids who grow up in the company of animals and who talk to those animals or to brooms and grandfather clocks and teacups are mentally disturbed.
Who will stand up and restore family values in our fables? How ironic that most of the movies that parents take their kids to depict children becoming adults without a full set of parents to aid them. It's certainly convenient from a dramatic perspective--it amplifies the emotional isolation of the protagonist and thus their subsequent heroism as well, and it avoids the uncomfortable emotional complexities of teenage rebellion from clouding the movie. Or perhaps the two parent family is too well-adjusted, on average, to offer dramatic possibilities?
Then again, I'm reading The Nurture Assumption by Judith Harris, one of the more famous books on child development, and the central thesis of the book is that children socialize each other more than parents socialize their children. It shows that the idea that parents are massively influential in the way their kids turn out is a cultural myth that's been propagated over the years with little evidence to back it up. Perhaps our fables simply do away with parents because they know that the most important influence of our parents is the genes they pass us, and that our subsequent development is driven more by our peers.
I'm only part way into the book, and I went into it with some skepticism (my parents would have a huge problem with the idea that they weren't highly responsible for the way I turned out) but it has definitely tickled my aha! nerve. Highly recommended for any parents out there or anyone interested in understanding how they turned out the way they turned out. Maybe our fables are smarter than we think.