This concept is not limited to sexual feelings and behavior by itself, and it is not synonymous with the libido in the broadest sense, which is invested in him by Freud. Psychosexual development – one aspect of ontogeny is closely associated with common biological organism's development, particularly sexual maturation, and future changes in sexual function. If you do not consider prenatal period, it begins with the formation of sexual identity baby, with a crucial role in this process is played by adults. Defining passport sex baby, parents and other adults are beginning to teach a child to sexual role, by showing them what it means to be a boy or a girl. Awareness of their gender, the child has already formed to 1,5 years, constituting the most stable, the core element of its identity. In 3-4 years the child has already consciously distinguishes the floor of surrounding people, but often associates it with a purely external signs, such as clothes, and admits the fundamental reversibility, the ability to change sex. In 6-7 years the child finally understands irreversibility of sex, which coincides with the rapid increase in sexual differentiation of behavior and attitudes, boys and girls on their own initiative choose different games and partners in them, show different interests, style of behavior. In addition to parents, a critical agent of sexual socialization is the society of their peers as well as the opposite sex. Estimating the constitution and the child's behavior in light of its own, much more severe than in adults, the criteria of masculinity / femininity, peers, thus confirm, strengthen, or conversely, raise questions about his sexual identity and sex-role orientation.