Your gender identity is your personal sense of being either male of female. It forms such a central part of your self concept, and I so resistant to change that you might have assumed that you were born with it. In fact however there are few biological connections between sex and behavior, and it is more openly accepted that for the most part children are not born with gender roles, but are rather placed in them by societal beliefs. For this reason most people reject theories of sex role development including biological and general schema approaches. Just imagine walking into a nursery decorated with dinosaurs, trucks and bright red and blue paint, isn't it easy to assume that the baby in the room is a boy? And likewise when walking into a different nursery and seeing dolls, and light blues pinks and yellows, wouldn't you feel safe in assuming that a baby girl lived there? Children don't necessarily recognize their gender roles until as early as age two, but are subject to stereotypes for their entire lives. In this way children learn, as they get older, what kinds of behaviors are expected of boys and girls in their society? .
According to Freud, throughout the development of a child there are several stages (each dealing with a sexual drive) that each child must go through and complete in order to grow and mature normally. Any incompletion of one of these stages will lead to ultimate problems later in life. The first stage lasts from birth to age one and a half and is called the oral phase. During this time the infant seeks oral pleasure, and gets total gratification through his mouth. Nursing plays a huge role in this stage and the nursing habits of the mother will therefore play a huge role in the development of the child. The oral stage then ends when the baby is weaned of his mother's milk and loses the sensory pleasures of nursing and of the psychological pleasure of being cared for, mothered, and held.