In the last decades of the twentieth century, a major change has occurred in the public understanding of prostitution, with the focus shifting from the sex worker to the client. On the social scientific side, studies on clients have growingly shed light on motivations and behaviors of men who buy sex. On the juridical-political side, in many countries across the globe a trend has emerged towards the criminalization of clients, represented as responsible for the perpetuation and proliferation of the sex market and for its oppressive and victimizing effects on sex workers. The aim of this paper is to retrace this turn and to discuss its political and cultural meaning, showing how the discourse on male responsibility in prostitution involves the risk of unilateral stances and partial views on the sex market. What I argue is that new gender-sensitive thinking on prostitution is needed, context-rooted and free from prejudicial understandings.