This article explores one female student teacher's experiences of learning to teach mathematics. Data included weekly emails and an interview through which Kelly expressed her struggle to be recognised as mathematical and to be heard in pedagogical relationships within a subject that is discursively aligned with masculinity. Analysis drew on feminist post-structural understandings of discourse and power relations. I identify an array of discourses of gender, mathematics, ability, confidence and complex micro-relations of power which shaped her 'identity work' and examine how she was able to reposition herself positively as a teacher of mathematics, resisting dominant transmission-based approaches to teaching mathematics. While the course sought to challenge traditional mathematical pedagogies, gendered ways of being mathematical were not confronted. I argue that teacher educators need to pay attention to the way power circulates to marginalise and silence some students and to focus on transformation of their own identity work.