This article locates Viagra, as both a biotechnology and a cultural event, in relation to shifting and specifically gendered interpretations of sexual function and dysfunction. While the clinical and market success of Viagra has prompted biomedicine and its popularizers to speak of a `new age' in human sexual relations, and accord it causal agency in effecting social change, I suggest that we might profit by attending to the social claims that underlie such hyperbole. The story behind Viagra is a complex history of the manner in which sexual function has been constructed and reconstructed in relation to a range of distinctly modern phenomena, including the rationalization and medicalization of sexuality, the increased importance of expert systems and knowledges in managing everyday life, and the expansion of consumer culture. Conclusions suggest some ways that we might think about the `sexually dysfunctional' as yet another `strategic unity' consolidating various operations of knowledge and power.