In response to articles in London's "Daily Mail" newspaper asserting that young children do not have the intellectual, social or moral skill to grasp the concept of heterosexuality and should not be exposed to lessons in bisexually or homosexuality, this paper argues that sexuality is pervasive in primary schools and suggests that the presumption of heterosexuality is the key matrix through which gender is understood by the children themselves, by most teachers and by other adults active in the school culture. Based on in-depth observation of and interviews with children in schools in London and central England, the paper contends that heterosexuality is a part of the stuff of every day life on playgrounds and in classrooms and is represented in: (1) imagined futures; (2) traditional games and rhymes; (3) versions of games involving running and catching; (4) sexist/sexual harassment; (5) assays into the world of "going out"; and (6) gossip networks. Throughout, the paper provides many examples of actions and conversations to illustrate the argument. The paper addresses the myth-making that developed in one classroom around the teacher's decision to come out as gay to his year 5 class (9-10 year olds) and the lessons that might be learned from that experience. The paper concludes by noting that cultures of schooling are, indeed, cultures of sexuality. Contains 16 references. (Author/MOK)