Some sociologists believe that children identify with being male or female by the age of three or younger. They have the capability to see differences between mom and dad and themselves. Also hormone productions influence feelings and identifications as well.
Are our gender related characteristics predetermined by genetics or influenced by our environment? What examples have you seen that prove or disprove this theory?
https://www.humanillnesses.com/Behavioral-Health-Fe-Mu/Gender-Identity.html