This study aims to develop a more fully theorised concept of biocitizenship as part of the teaching of intersex in critical approaches to sex education. It advances a perspective in which the options of students, as future parents and as biocitizens, are not limited to compliance to biomedicine, but one in which formal education experiences might prepare them to be neighbours and parents who, as allies of intersex family/community members, can engage in political activism to effect change where deemed necessary. Data take the form of classroom talk drawn from a study based in an Aotearoa/New Zealand secondary school, focusing on transgressive acts of citizenship by an intersex activist visiting the sex education classroom and assisting students with social justice projects. Transcripts of audio-recorded classroom interactions are analysed using a version of critical discourse analysis that directs attention to semiotic modes such as visual cues of bodies as well as affect. Findings reveal that biocitizenship can also include those who accept intersex bodies, altering established practices to accommodate those bodies and the people who live them.