Heterosexuality

Heterosexuality is romantic or sexual attraction or behavior between persons of opposite sex or gender in the gender binary. As a sexual orientation, heterosexuality refers to "an enduring pattern of or disposition to experience sexual, affectionate, physical or romantic attractions to persons of the opposite sex"; it also refers to "an individual’s sense of personal and social identity based on those attractions, behaviors expressing them, and membership in a community of others who share them". The term is usually applied to humans, but it is also observed in all mammals.