monosexism

The idea that sexual attraction to one sexual or gender identity (heterosexuality, or homosexuality) is somehow superior to that of sexual identities that apply attraction to more than one sexual or gender identity (bisexuality, pansexuality). (Serano, 4)

heterosexism

“where heterosexuals are viewed as more legitimate than homosexuals” (Serrano, 44)

Ties in directly with heteronormativity, gender determinism, and even essentialism, in that heterosexual interactions are standardized as the all-being “normal”.