At a young age boys and girls are playing with toys, but the difference is that the boy is playing a GI joe while the girl is playing with a barbie doll. same as colors boys tend to be on the dark side, while girls tend to be on the lighter bright colors. but who is to say that boys can't like "girly" colors or girls be into action figures. society tells them, their peers tell them, their parents tell them. Because they don't want them to be "different".