After theorizing the interactions between the conscious and the unconscious, Freud devised the personality into three structures: the id, the ego and the super-ego. The id, most closely related to the unconscious, represents the libidinal (infantile) desires, the ego represents reason and the super-ego represents the critical, social and moralizing part. However, these are not parts of the mind; rather, they are functions of the mind. The ego functions to appease the desires of the id in realistic ways or to cloak (from the id or from society) those desires in other ways. The id wants immediate gratification and the super-ego seeks to act in rational and socially appropriate ways. The super-ego is thus the internalization of authority figures. It makes sense that when a subject's super-ego develops, that subject's Oedipus Complex ceases to be; that inner child seeking love from the mother and hatred (or rivalry) of the father becomes more like a parent himself. Freud thought that neuroses stem from sexual trauma at a young age or when a person has a faulty super-ego; that is, he cannot channel or suppress the id effectively.
Also as part of the dissolution of the Oedipus complex, Freud theorized that the males deal with it through castration anxiety. The male child fears his rival (father) will castrate him as punishment for desiring his mother. The female child has what Freud called penis envy meaning she desires to have the power that the males have.
One negative reaction to this is that it is sexist. There is so much emphasis on the power of the phallus (the male's power) that it seems Freud places an inherent or natural inclination that males and females are born with a psychological inclination that power resides in the phallus. Some feminists have challenged this notion, saying that this is just the result of a patriarchal history in which the male has, until recently, been the breadwinner, the laborer and the dominant gender in relationships and social institutions. They argue that this is a social, not a genetic, development.
Perhaps the main criticism of Freud's theory is that it is not testable. As the unconscious is hidden, it cannot be tested using the traditional scientific method. His theories were mostly based on clinical impressions; not empirical data.