girl roles-playing princess, etc.

[limewave]

Umm... Have your brother get her a bike or trike or whatever - and turn the damn tv off. Take her to a park with a sandbox or some swings. Give the kid something else to do or be interested in - rather than letting them figure out what they "want" to get into.
SpinSpinSugar

Easier said than done. We take DD on bike rides all the time. Play at the park. DH built her a huge sandbox that she loves to play in. And the only TV she watches is Handy Manny in the AM when we're getting ready for work. She loves all of those things . . . but she also loves Princesses. I think this has more to do with her older cousin--whom she ADORES.

Unless you homeschool and don't let your kids play with other kids . . . then you can't control everything they are exposed to.