At the pool she will be expected to cover her breasts. Clearly there are important biological differences between boys and girls. These differences are reflected in our differential labelling. However, many of the differences between individual boys and girls are induced by our different expectations and behaviors toward boys and girls. Many confuse these culturally-induced differences with the biological differences, and try to place artificial limits on members of each sex.
Girls are encouraged to become nurses and hygienists, boys become fighter pilots and engineers.
Boys are expected to be the sexually dominant, girls are expected to take care of the gifts on special occasions. The effects of these stereotypes will be to limit the development of individuals. The problem lies in our doing so without being conscious of abstracting.