Gender development is an age old "tradition". As we mature, we grow apart as our identities as male or female are formed. This change can be linked to biology, and the reproduction of the genes to interact with chemical signals... But if we look at the wild, these gender relation only serves to create animal social standpoint, such as a pack of dogs & a male leader. Male and female dogs both wrestle, chase, and chase after the same ball together. For some reason the differences formed in gender development cause stronger development than for that of animals. The factor that causes this anomaly is society.
Society is everywhere around us, telling us what to do, what we are expected to do, and what people will think of what we do. All around us, in the newspapers, on TV, on the radio, on the Internet, we find stories of sexually discrimination of pride in being a man or a woman. The time when natural gender development is during one's teen years, creating a release of hormones during which one gender realizes the importance of another. Teens are also known for unstable minds (in terms of personal happiness) and are constantly looking to fit in. Teens, more than others, look online and to other sources to find out what they should do. Even in the school yard the students gossip to one another about what is acceptable and what is not.
This key point in the lives of many people is the ideal time to discover an "identity". Such an identity normally involves embracing the semi-stereotypical aspects of one's gender. Young ladies begin to act like "women", learning the necessities of shopping, fashion, and self-respect. Young men learn the important aspects of competition and indifference to others. Thus, through experiences with society, humans develop their gender & their gender "identity", more so than in nature.