Ovotesticular disorder of sex development (OT-DSD), previously known as true hermaphrodite, is a rare disorder of sexual differentiation in which the gonads of an individual are characterized by the presence of both mature ovarian and testicular tissues. The diagnosis has traditionally been applied only if an individual has 1) histologically verified ovarian follicles or proof of their prior existence (e.g. corpora albicantia) and 2) seminiferous tubules or spermatozoa. This paper introduces you to a 14 year-old, who presented with primary amenorrhea and enlarging abdominal mass, underwent exploratory laparotomy, salphingooophorectomy, histologically diagnosed as a possible case of a true hermaphrodite and chromosomally diagnosed as 45XO/46XY who developed endodermal sinus tumor, a germ cell tumor, considered highly malignant.