This article sets out to explore the dilemmas present in the reproductive practices of people affected by rare hereditary diseases, focusing on the use of diagnostic tests and the practice of genetic counselling in Brazil. The development of technologies capable of mapping 'genetic flaws' prior to conception or in prenatal consultations has led researchers to consider how these technologies may be shaping contemporary subjectivities related to kinship and guiding reproductive decisions based on knowledge of our 'genetic heritage.' Genetic counselling has emerged in this setting as a modality of health knowledge and information capable of assisting people, especially women, in their reproductive choices. In Brazil, access to these technologies and their use has proven to be unequal and heterogeneous. I argue that the idea of 'choice' that permeates genetic counselling needs to be problematized by considering the social, cultural, economic, affective and moral frameworks in which women are inserted and that inform and/or determine their reproductive decisions. Based on this premise, I analyse how families 'at risk' of rare hereditary diseases deal with the idea of 'genetic inheritance' in relation to the 'wish to have children', and the impasses surrounding the idea of 'informed choice' when we evaluate this rhetoric in the context of the shortfalls in access to healthcare and the limits to reproductive justice in Brazil.