Genderism is the cultural belief that gender is a binary, or that there are, or should be, only two genders — male and female.

Society advances that belief that one’s gender is inherently linked to the sex in which they were assigned at birth which is determined by the presence of a penis.

Gender assignment can reinforce negative attitudesbias, and discrimination towards people who display expressions of gender variance or nonconformity and/or whose gender identity is incongruent with their birth sex. Genderism is of particular relevance to individuals who fall within the transgender spectrum, and is the overarching ideology responsible for transphobia and gender bashing. In addition, much like how transphobia is parallel to homophobia, genderism is said to be parallel to heterosexism. (Source: Wikipedia – Genderism)