Freud believed that humans went through a series of stages in psychosexual development. Passing through these stages required the id's impulses to be controlled and resolved by the ego. However if the impulses were not satisfactorily resolved then the lingering unconscious conflicts could lead to psychological problems in later life. In the Oral Stage (birth to 18 months) the child is focused on the mouth as a way of seeking pleasure because of its requirement for nursing. If the child's weaning is traumatic, in later life any unresolved conflicts may manifest as a preoccupation with oral activities such as smoking, drinking, eating or bite his or her nails or chew pencils and pens. The Anal Stage (18 months to three years) is a time in which pleasure is based on eliminating and retaining bowel movements and gaining control over them. In terms of conflicts during this stage, the end result can be an obsession with cleanliness, perfection, and control (anal retentive) or they may become messy and disorganized slobs (anal expulsive). During the Phallic Stage (ages three to six) the attention witches to the genitals as boys and girls learn that they are differences between the genders and become aware of the similarities and differences between them and their parents. Freud believed that during this stage boys develop unconscious sexual desires for their mothers and come to see their fathers as rivals for her attention and affection. He also believed that boys develop a fear that their father will punish them for these feelings, such as by castrating them. This group of feelings is known as Oedipus Complex. Similarly girls were supposed to go through a similar attraction with their father and competition with their mother termed the Electra Complex. Girls were also thought to develop penis envy over not having male genitalia. In the end, the conflicts were