This paper arises from an online discussion project in the United Kingdom, funded by the Nuffield Foundation, in which higher education students and staff were invited to respond to a series of statements about sexual orientation in the context of schooling. This paper suggests that the silence of relative non-participation may have been exacerbated by other levels of silence operating within the wider social, political and educational context of the project. Analysis of data from the web forums revealed the perception of children as asexual beings, the sexualisation of homosexuality, and a tendency to separate the public and private domains. We also found some political correctness reflecting the legitimised diversity discourses operating within the university context without necessarily addressing the more uncomfortable questions behind them. Participants also imagined anxieties on the part of parents, teachers or pupils and diverted the discussion to other topics of concern, which may have served to protect them from direct engagement with the issues under discussion. In combination, we suggest that these factors create multiple layers of silence that serve to support the construction and maintenance of heteronormativity as well as demonstrating the power of the heterosexual matrix in action. (Contains 1 table, 2 figures and 2 notes.)