Biology is instrumental in establishing and perpetuating societal norms of gender and sexuality, owing to its afforded authoritative role in formulating beliefs about what is “natural”. However, philosophers, historians, and sociologists of science have shown how conceptions of gender and sexuality pervade the supposedly objective knowledge produced by the natural sciences. For example, in describing animal relationships, biologists sometimes use the metaphor of marriage, which brings with it conceptions of both cuckoldry and male ownership of female partners. These conceptions have (...) often led researchers to overlook female behavior and adaptations, such as female initiation of mating. Such social norms and ideologies influence both theories and research in biology. Social norms of gender and sexuality also influence school cultures. Although awareness of gender issues has had a major impact in Sweden during recent years, the interventions conducted have been based on a heteronormative understanding of sex; this has rendered sexual norms a non-prioritized issue and thereby rendered non-heterosexuals invisible in teaching and textbooks. Since this research was published in 2007 and 2009, norm critical pedagogics have been included in the Swedish National Agency for Education’s guidelines for teaching. This inclusion represents one way to tackle the recurring problem of heterosexuality being described as a naturalized “normal” behavior and homosexuals, bisexuals and transsexuals being described from a heteronormative perspective. In this paper, I employ gender and queer perspectives to scrutinize how animal sexual behavior is described and explained in Swedish biology textbooks. The analysis is based in gender and queer theory, feminist science studies, and evolutionary biology. The article begins with an outline a discussion of my theoretical framework, relating gender and queer perspectives on evolutionary biology to a discussion of queer methodology. I then scrutinize some empirical examples drawn from five contemporary biology textbooks used in secondary schools (by students aged 16-18 years old). Finally, I discuss the implications of the textbooks’ representations of animal sexual behavior, the problems of and need for a “textbook-version”, and providing examples of what an inclusive approach to biology education might look like. (shrink)