Gender role theory posits that boys and girls learn the appropriate behavior and attitudes from the family and overall culture in which they grow up, and that non-physical gender differences are a product of socialization. Social role theory proposes that social structure is the underlying force behind gender differences, and that the division of labor between two sexes within a society motivates the differences in their respective behavior. Division of labor creates gender roles, which in turn, lead to gender-specific social behavior.
Family is the most important agent of socialization because it serves as the center of a child's life. Socialization theory tells us that primary socialization - the process that occurs when a child learns the attitudes, values and actions expected of individuals within a particular culture - is the most important phase of social development, and lays the groundwork for all future socialization. Therefore, the family plays a pivotal role in the child's development, influencing both the attitudes the child will adopt and the values the child will hold. Socialization can be intentional or unintentional; the family may not be conscious of the messages it transmits, but these messages nonetheless contribute to the child's socialization. Children learn continuously from the environment that adults create, including gender norms.
For example, a child who grows up in a two-parent household with a mother who acts as a homemaker and a father who acts as the breadwinner may internalize these gender roles, regardless of whether or not the family is directly teaching them. Likewise, if parents buy dolls for their daughters and toy trucks for their sons, the children will learn to value different things.