Gender is learnt
The environment in which a baby is reared with respect to gender begins to take shape prior to birth. ... Upon assignment of sex at birth, a significant environmental role begins in gender development because the parents usually rear the child as either male of female, with all of the associated social interactions. We cannot say whether particular gender identity is truly an inborn characteristic, or even if it remains unchangeable through the course of an individual’s lifetime. We as children, young adults get biased towards a particular gender identity to be molded during the first few years and, in some cases, perhaps even in later years. Clearly though, as gender development progresses in children, an acceptance and personal expression of a gender identity occurs. This gender identity is then hard to get rid of and sticks with us for life.