This research explores the ways and devices through which we learn to think about identities in school, to order them as good/bad, better/worse, or normal/weird, and to privilege certain communities over others. It is assumed that students learn this way of thinking about identities and their relationships, and therefore it is a type of knowledge that can be located and traced through the school curriculum (formal and informal). In short, the guiding questions of this study are: how do we learn to distinguish and assess normality and difference? And what are the systems for reasoning normality and difference learned in school? In order to answer these questions, different educational levels are approached (from primary education to secondary education), focusing on curricular terms in the subjects of Social Sciences and Natural Sciences.