A rare disorder of sex development (DSD) due to a defect in metabolizing testosterone to dihydrotestosterone and characterized by incomplete intrauterine masculinization which ranges from a female genitalia with a blind vaginal pouch to a fully male phenotype with pseudovaginal posterior hypospadias and micropenis. The disease is 46,XY disorder of sex development due to 5-alpha-reductase 2 deficiency (MONDO_0009923). Also known as: 3-oxo-5 Alpha-steroid Delta 4-dehydrogenase deficiency, 46,XY DSD due to 5-alpha-reductase 2 deficiency, 5 Alpha steroid reductase 2 deficiency, Male pseudohermaphroditism due to 5-alpha-reductase 2 deficiency, pseudovaginal perineoscrotal hypospadias, steroid 5-alpha-reductase deficiency.