Abstract : This article examines medieval ideas about the human status and access to the sacraments of monsters: both the strange races on the edges of the known world, and individual portentous births. The article shows that medieval discourse about monsters was not homogeneous. As far as monstrous races were concerned, Augustin, who attached little importance to physical appearance and tended to include the races in his “universalist” vision of humanity, constituted a reference that could not be ignored. However, from the 13th century on, the idea of a necessary concord between body and soul made this position harder to maintain, whereas the taking into account of other criteria (social and religious behaviour, linguistic capacities) lead to the exclusion of pygmees from human nature. On the other hand, in canon law and theology the humanity of monsters born from human parents was more or less taken for granted. The question of their baptism only arose with respect to conjoined twins and then the question was not whether, but as how many persons they needed to be baptised. Paradoxically, the idea that children, who do not look human should not be baptised is found in civil, not canon law, from the 14th century on. In line with Roman law, the form of the body, and not the soul was here considered decisive, a principle that went together with the idea that certain monstrous births were due to bestiality, although medieval physicians and philosophers generally refuted that belief. In the Early Modern Period, the canonists began, however, to assimilate the position of civil law. As far as hermaphroditism is concerned, medieval authors sometimes admitted the existence of a perfect intermediary between male and female, but more often considered that one gender was necessarily dominant. Interestingly, the criteria for classification were as often social as anatomical. The medieval Church authorized marriage of all hermaphrodites except “perfect” ones, but strictly prohibited alternating sexual roles, a reproach formulated against homosexuals, whom hermaphrodites were often associated with. Ordination was even more of a problem, because the Church excludes women. According to some canonists, only “male” hermaphrodites may be ordained; others excluded all hermaphrodites on the ground of irregularity. The article terminates with a reflection on the relative importance of medieval debates about monsters, among other things by pointing out that the greater richness of discussions about hermaphroditism in medieval Islamic law seems to correspond to the greater importance of sex difference in Middle Eastern society.