'Heteronormative assumptions interconnect with the institutionalization of heterosexuality and also shape the doing of heterosexuality and being and becoming heterosexual – as well as shaping the doing and being of alternative sexualities. [...] we cannot regard gender, sexuality and heterosexuality as phenomena of the same order, mapping easily on to each other. In particular, we cannot afford to reduce sexuality to the heterosexuality–homosexuality axis, or any other means of classifying sexualities, or reduce heterosexuality to sexuality alone, to one form of sexuality among others. The connections between heterosexuality and gender are much tighter and much more reciprocal than the links between gender and sexuality or sexuality and heterosexuality – precisely because heterosexuality is not only sexual. This is not to say that the ‘sexual’ in heterosexual is unimportant – for it is forms of sexual practice (as well as other non-sexual practices) that help define what constitutes a heterosexual and what defines its perverse other.'
Stevi Jackson, 'Gender, Sexuality and Heterosexuality: The Complexity (and Limits) of Heteronormativity', Feminist Theory, 7(1)