Life Orientation sexuality education in South Africa faces many pedagogical challenges, not least among which is that it is sometimes perceived as irrelevant to learners' real interests and concerns. Learners report that the content is repetitive and that they learn more from peers than from the reiterated lessons of risk and disease avoidance that permeate sex education messages. In this article we describe the world of the study site--a "single sex" school--as consisting of diverse informal student sexual cultures in which repertoires for the development of learner sexual identities are developed, negotiated and transmitted. The study is based on detailed ethnographic immersion in the study site which generated rich data drawn from in-depth interviews, focus groups, observations and solicited narratives. We argue that even the enlightened, tolerant "best practice" form of sexuality education that takes place at the study site fails to take diverse learner identities, lifeworlds and experiences seriously as a pedagogic starting point, but rather tends to homogenise learners and to impose on them what they need to learn. A more empowering form of sexuality education would take seriously how young people understand themselves as sexual subjects located in unequal ("raced" and classed) social contexts.