To study the curriculum, as Bernstein argues, is to begin to understand what it is possible to think and who can think it. This powerful notion will underpin an exploration of the impossibility of women's studies courses in the context of the UK higher education system. Whereas women's studies has become a recognized subject area in other countries such as the USA, it has struggled for legitimacy in the UK since it began to be developed in feminist courses, largely within sociology degrees, from the 1970s. Based on archival research and interviews with academics and students in several case study universities, this article will examine how the boundaries around legitimate academic knowledge are maintained when certain curricular innovations are proposed. The social construction of academic knowledge involves a complex interplay between politics, knowledge, power relations, and the structure of the higher education system.