Article: Growing Up, Acting Out

He'll Just Say No
You ask your son to clean up his room, and instead of assuring you that he'll get to it, he flat out refuses your request. "I don't feel like it," he says.

At this age, a child is struggling to be in charge of his own world and views his bedroom as a space over which he should have complete control. He also may be testing boundaries by defying your requests. But while this may explain his defiance, it doesn't justify it. "You need to set clear rules about what you expect from your preteen--and to establish consequences if those rules are broken," says Laurence Steinberg, Ph.D., author of The Ten Basic Principles of Good Parenting. Let your child have some input into what those rules and consequences should be. Involving him will make him feel his views are respected—and that goes a long way at this age. But don't hesitate to lay down the law if your child wants to do something that you feel is unsafe, unhealthy, or counter to your values.

http://www.parents.com/parenting/better-parenting/teenagers/growing-up-acting-out/