It's the same idea, it's establishing gender indentity. Gender roles in society are learned. Boys are SUPPOSED to like blue and play rough and play sports. Girls are SUPPOSED to like dancing and horsies and pink. If we weren't bombarded by suggestions via TV/print/society/our family, you think the same result would occur? It's been ingrained in the minds of people at an early age how they should act since they are a boy or girl.