This is the set of ideas, social norms, beliefs, and culture that govern people whose gender identity corresponds to the one assigned at birth, and people who also identify as heterosexual. This type of social construction is considered the only model for sexual-romantic and parental relationships, and it establishes advantages for people who abide by this system.
This belief and idea is considered a type of discrimination against the LGBTIQ+ collective, as it makes sexual diversity and people who do not identify with these ideas invisible. The term was coined in the 1990s as part of queer theory to visibilize the oppression against people who did not feel part of this social construct. Today, many societies still abide by this belief and they discriminate other collectives.