It starts out so pure. Parents sign their kids up for soccer, basketball or other sports--all for the right reasons--to improve fitness and coordination, learn new skills, build character and have fun. With child obesity rates skyrocketing and budget-crunched schools eliminating physical education classes, organized sports are playing an increasingly important role in getting today's kids moving.

Yet all too often, when the whistle blows and the game begins, a strange phenomenon occurs. "People start to think, 'If you're not a winner, you're a loser,'" says Kevin Daugherty, youth sports specialist for the American Sport Education Program, a Champaign, Illinois-based group that provides resources for coaches and parents. And that's when destructive behavior starts.

Horror stories abound of "trash talking," fighting and other forms of disrespect toward opponents, officials and even teammates. And, sadly enough, the offenders are often the parents.