In addition to the diagnoses mentioned above, pediatric urology also involves surgical correction of a wide variety of other genital abnormalities in both male and female patients. Many of these disorders can be classified under the term disorders of sexual differentiation. The two most commonly encountered disorders are termed urogenital sinuses and cloacal abnormalities and occur exclusively in females. A urogenital sinus occurs when the vagina and urethra fail to form two distinct openings. As a result, these girls may have issues adequately draining the bladder. In otherwise healthy children, complex reconstructive surgery is typically undertaken in the first year of life in order to create two distinct openings and to create more cosmetically normal external female genitalia. A cloacal abnormality occurs in female patients when the urethra, vagina and rectum all exit the skin through a single opening. Due to the involvement of the rectum, these girls require surgery in the newborn to create a colostomy to provide drainage of the rectum. As in patients with urogenital sinuses, complex reconstruction is typically performed in the first year of life and focuses on separating the urethra, vagina, and rectum and creating three distinct openings on the skin. In patients with complex genital abnormalities, life-long urologic follow-up is necessary to assure normal bladder function and appropriate vaginal anatomy.