Recent codifications of the English and Scottish law of sexual offences have highlighted significant difficulties with the manner in which the criminal law purports to regulate adolescent sexuality. While it is rare for consensual sexual activity between adolescents to be regarded as warranting prosecution, legislators have shied away from reflecting this practice in formal rules. Legislators have instead preferred to maintain excessively broad prohibitions, although the Scottish legislation is not as extreme as the English in its breadth. This article explores the justifications offered by legislators for this approach, and identifies five problems with it: first, the arbitrary nature of prosecutorial discretion; secondly, the deliberate subversion of the presumption of innocence; thirdly, the consequences in terms of alternative verdicts where more serious offences are charged; fourthly, a distorting effect on other aspects of the law of sexual offences and fifthly, an abuse of the expressive function of the criminal law. It argues that a rational system of rules in this area of the criminal law is unattainable without legislators being prepared to engage openly in a discussion of the extent to which adolescent sexual behaviour is properly of public concern, which has not been a feature of recent debates.