The trauma induced by the child’s discovery of anatomical difference between the sexes (presence or absence of the penis) gives rise to the fantasy of female emasculation or castration.
[2] According to Freud the early stages of the child’s psychosexual development are characterised by polymorphous perversity and a bisexual disposition, and are the same for both sexes.
For the boy, anatomical difference (the possession of a penis), induces castration anxiety as a result of an assumed paternal threat made in response to his sexual thoughts and activities.
In the case of the girl the absence of a penis is experienced as a deprivation, a wrong suffered which she attempts to deny, remedy or compensate for by seeking to have her own child.
[6] In his later work Freud includes the castration complex in the category of primal phantasies that are universal in their derivation from the incest taboo, the necessary founding condition for all human social and cultural formations.