Oral stage is ranged from the day the baby is born until he is one-and-a-half years old. A child's personality development is easily affected by the lack of food and care from people around him. Anus stage begins when the child starts to learn to control his urination and excretion; this stage extends from one-and-a-half years-old to three years-old when the child can go about freely, it is also the stage of ego. In the beginning of phallic stage that ranges from three to six years old, the child begins to develop special liking towards people of the same sex, then gradually this special liking turn its target to people of different sex. When the child is about to shift his special likeness to the opposite sex, if those who raised him up are mixed up themselves in their sex roles, this will lead the child to turn out to be a homosexual or a bisexual. Single-parent families with abnormal sexual relationship or incest can also cause a child to grow up becoming a weirdo. Superego can at this moment step in and give rise to a training period for children like the above. Here we need to emphasize psychological self-defensive mechanism again: many people today wants to satisfy their desires on the one hand and gain society's acknowledgements on the other, and often they have to go through a lot of psychological struggles themselves. People then managed to find ways to lessen the pressures they bear when they come to setbacks and failures.