Pure gonadal dysgenesis or Swyer's syndrome is a genetic disorder of the sex chromosomes characterized by being patients with a female phenotype but with genotype XY, absence of functional gonadal tissue that prevents the formation of the antimüllerian hormone and normal formation of structures derived from the duct Müller. This can occur by mutations of different genes such as SRY of the Y chromosome, important in the process of sexual determination or as SOX-9 and WT-1, keys in the production of proteins involved in the same process. It courses with gonadadas acintadas, ambiguous structures that predispose to neoplasms such as dysgerminomas and gonadoblastomas. Bilateral gonadectomy is recommended as shown in a 16-year-old female phenotype and 46XY genotype.