Zach Plante is close with his parents - he plays baseball with them and, on weekends, helps with work in the small vineyard they keep at their northern California home. Lately, though, his parents have begun to notice subtle changes in their son. Among other things, he's announced that he wants to grow his hair longer - and sometimes greets his father with "Yo, Dad!" "Little comments will come out of his mouth that have a bit of that teen swagger," says Tom Plante, Zach's dad. Thing is, Zach isn't a teen. He's 10 years old - one part, a...