Electra complex classical psychoanalytic theory, the child's identification with the same-sex parent is the successful resolution of the Electra complex and of the Oedipus complex; his and her key psychological experience to developing a mature sexual role and identity. Sigmund Freud instead proposed that girls and boys resolved their complexes differently—she via penis envy, he via castration anxiety; and that unsuccessful resolutions might lead to neurosis. Hence, women and men who are fixated in the Electra and Oedipal stages of their psychosexual development might be considered "father-fixated" and "mother-fixated". As a psychoanalytic term for daughter–mother psychosexual conflict, the Electra complex derives from
Penis envy by removing the man from the penis or the penis from the man). Freud's theories regarding psychosexual development, and in particular the "phallic stage", were early challenged by other psychoanalysts, such as Karen Horney, Otto Fenichel and Ernest Jones, though Freud did not accept their view of penis envy as a secondary, rather than a primary, female reaction. Later psychologists, such as Erik Erikson and Jean Piaget, challenged the Freudian model of child psychological development as a whole. Jacques Lacan, however, took up and developed Freud's theory of the importance of what he called ""penisneid" in the unconscious of women"