[klenwell]

For a comprehensive scholarly treatment of this argument (with which I wholly concur), see Judith Rich Harris and The Nurture Assumption.

Her Wikipedia article offers a quick summary:

https://en.wikipedia.org/wiki/Judith_Rich_Harris

In short, kids, especially teenagers, aren't out to be like their parents. They want to be like their peers. And what we often see as the effects of good parental influence or supervision may simply be heritable behavior.