This paper uses a post-structuralist perspective to articulate the conceptual limits of the discourse of 'coming of age' as a means of examining concerns about the representation of young female sexuality in the media. Through analysis of the content and production contexts of the films Lolita (1997) and Thirteen (2003), it argues that the discourse of 'coming of age' is grounded in a contradictory logic that produces conflicting aims: a desire to preserve the innocence of youth and a simultaneous expectation that they 'grow up'. Using techniques of Derridean deconstruction, the paper examines the effects that this logic produces in terms of how key aspects of 'coming of age' contradict what the discourse sets out to determine and how this contributes to perceptions of youth sexuality as problematic. It will be shown that these conceptual contradictions remain unseen in attempts to make sense of the controversial aspects of the two films: the issue of pedophilia in Lolita and the problem of teenage rebellion in Thirteen. Importantly, the deconstructive reading suggests that it is the paradoxical underpinnings of this approach to youth identity that enables the discourse to be thought at all. By working to recognise this, it is possible to move beyond the limits of the discourse and think differently about youth in response to the perceived threat posed to young people by media representations of adolescent sex and sexuality.