Karen Horney was an important psychodynamic psychologist. She refined and changed many of Sigmund Freud's theories about child development, as did many of her contemporaries. However, she stood out for her most important argument against Freud's theories.

Freud stated that women feel inferior to men when they find out that men have a penis and they do not - he called this "penis envy". He also indirectly asserted that a woman's place was in the home, and that a woman trying to compete with men working outside of the home were suffering from an unconsious penis envy. Horney refuted those theories.

Horney argued that girls do not feel inferior to boys, effectively denying the existence of this so-called "penis envy". She said that early psychoanalytic views were based on cultural influences (the view that women should not work outside the home), and had no basis in science. Horney's arguments pointed out one of Freud's many flawed or incorrect views.