In the period following a global pandemic, the promotion of health and wellbeing is a priority area for schools. This accompanies growing calls for health and wellbeing education to be delivered through a whole-child/whole-school approach that connects across subject areas. While it may be clear to most people that a purely scientific sexuality education is undesirable, it is also clear that biology plays a vital role in developing students' understanding about a variety of health and wellbeing topics, including those around sex, sexuality and sexual health. In this article, we explore the contribution of the biology teacher to an integrated health and wellbeing education in schools through a case study comparison of the English Relationships, Sex and Health Education curriculum and the English biology curriculum. Biology teachers in England and many other national and regional jurisdictions operate in a compartmentalised system which can create frustration and anxiety for both students and teachers when navigating the complexities of how sensitive topics are delivered in different disciplinary siloes. Epistemically insightful approaches, conceptualised at the macro-, meso- and micro-level of school organisational structures, may provide a way for biology teachers and educational leaders to address and overcome some of these challenges.