Freud's psychoanalytic theories
The final stage of psychosexual development is the genital stage. This stage begins at the age of eleven, lasts through puberty, and ends when one reaches adulthood at the age of eighteen. The onset of puberty reflects a strong interest from one person to another of the opposite sex. If one does not experience fixation in any of the psychosexual stages, once he or she has reached the genital stage he or she will grow into a well-balanced human being.