El Ch* Well, I think part of that can be explained best by
  merging Piaget and Vygotsky; -I think piaget has it right with
  regards to stages; there are general stages that children go
  through - and i think Vygotsky has it right with the social
  aspects of learning. Anyway, long story short, it seems that
  around 6-8 years old, parents are no longer as important to
  children as their peers are.... and sometimes teachers too. But
  by this point, parents are more the roles they play; part
  police, part teacher, part friend, part parent from the kids
  point of view - whereas "pure friends" (friend-friends one might
  say) have the greatest influence on interests and development.
  That includes the constructed friends of TV, youtube, characters
  in video games, pets, etc. And... well, that's where they're
  going to learn about sex at that point. By the time they're
  interested in the subject, their parental influence are already
  much less but the wide range of friends is far more influential.
  Does media affect the mind? Well, in my mother's day, comic
  books were "works of the devil" but she still read and collected
  them, even as preachers and polititians and scientists alike
  cried "These are bad for your kids" But they weren't. [or
  perhaps they *were* - I'd be curious for someone to do a
  sociocultural study to find out the influence of comic books
  from my mothers's generation compared to video games compared to
  movies, tv shows - through the generations... and see what
  influences they had (if any) on future behavior.