This work aims to answer the eternal question of the disinheritance of the child under legal age. To this end, we will approach the institute of disinheritance, its foundation and its jurisprudential evolution. We will also address the capacity and responsibility of the child under legal age and the emancipated minor. Subsequently, we will carry out the study of the disinheritance of the child under legal age, subject to the whim of the specific disinherited causes, since each of the causes provided for in art. 853 Spanish Civil Code are endowed with their own idiosyncrasy, being very complicated, if not impossible, to deal with the subject of this work apart from the vicissitudes that can occur according to the imputed facts. Finally, and before submitting this study to a reflective recapitulation, we will study the problems posed by reconciliation between the ascendant and the disinherited minor, since reconciliation, as a means that allows disinheritance to be rendered ineffective, presents its own vicissitudes when the heir is a child under legal age.