In the Phallic stage, there are two complexes that arise:
Oedipus complex - boys develop incestuous feelings toward their mother.
Electra complex - girls experience penis envy (proposed by Carl Jung).
-> These complexes also form incestuous feelings to their parent of the opposite sex, but this is repressed and ends up leading to the child forming a 'role model' view to their same-sex parent and give up their incestuous feelings.
It's not the Oedipus or Electra complex themselves that cause our gender behaviour, it's the identification of the same-sex parent that causes gender behaviour - Children identify with their same-sex parent as a way to resolve the conflict. This involves the children taking on the gender identity of their same-sex parent and internalising their behaviour.
X - Lack of research evidence - Freud's theory is based on a singular case study of little Hans. Han's behaviour may be atypical, and he may not represent the behaviour of all male children.
X - Feminist psychologists believe that Freud/Jung's ideas lack temporal validity as they are rooted in antiqued 19th century views about women as the inferior sex.
X - Green (1978) found 37/39 children raised by gay/transgender parents developed stable gender identities. This is also the case of children raised in single parent families.