Nowadays, as societies industrialize, the muscle power declines. It gives people more options and further reduces gender differences. Therefore most women get the same social standing as men get. However, there are still some unfairness between male and female, such as sexism: some girls do not do better in the real world, even though they do better in school than boys.
It is no doubt that there are biological differences between man and woman. As we know that the development of bones, muscles and nerves in baby girls is faster than boys, so girls show more intelligence than boys at early age. Perhaps it is the reason why girls usually do better in school than boys.
Another cause is our society. Even though the federal government puts a great deal of energy to improve gender equality, unfairness between two sexes still exists. The classic example can be the difference in earnings between men and women in the world.
The most important reason for the lower earning of working women is the kind of work they do, mostly these work are clerical and service jobs. And most people consider these jobs as "women's work". Another cause of this income gap has to do with the family. When a family has children, our society always thinks raising kids is a women's responsibility. Pregnancy and raising small children keep many younger women out of the labour force. As a result, the number of women workers is less than male workers. The third reason is the discrimination against women. Although discrimination is illegal, sexism still exists in our society. Because of this unfairness attitude, most women are concentrated in low paying jobs.
Third cause is due to baby's education. As a boy grows, society and his parents teach him to be rational,