Este seeks to contribute to the discussions that intersect issues relating to population government with processes of state reproduction of inequality. By qualitatively analysing judicial proceedings on criminal cases against adolescents in Buenos Aires in 2016, it focuses on conditions specific to the criminal system that strengthen the use of deprivation of liberty for the most vulnerable populations. The analysis appeals to feminist state theory, including the interpretative and material dimension of institutional practices, as well as the ways in which gender and age are processed; in addition, it reflects on the file as the object of constructing realities. The article concludes that what shapes the causes of heavy measures such as deprivation of liberty – still in a specialised and human-rights-compliant criminal system – is a complex plot between: moral appraisals of bailiffs on the paths of teenagers and their families, prior to and during the passage through the system, how families manage to negotiate such interpretations, and the bureaucratic inertia that underpins the guarantee of rights.