In this response to Damien Riggs' analysis of sex education websites, the author draws on Foucault's understanding of knowledge, power and governmentality to understand how some forms of knowledge about sex and sexuality become normalised "official knowledge" that frame institutional policies and practices and shape everyday discourses. Foucault provides a framework for analysing sexuality as a modality of government that produces and manages what types of knowledge are, or are not, "knowable" about sex, gender and sexuality. The author then considers the implications for those who are marginalised or silenced in "official" knowledge cultures of this kind. Theory, she argues, provides tools for disrupting normative knowledge about childhood sexuality, which frames educational practices and everyday discourses. (Contains 1 note.)