The entire genitourinary system is subject to a variety of possible insults from the beginning of development through adult life. Tissue loss may result from acquired disease as well as congenital disorders-infection, trauma, malignancy, iatrogenic injury, obstruction, and other disease processes. Also, many children are born with conditions that render their urinary tract organs suboptimal or nonfunctional, such as spina bifida or renal parenchyma loss from posterior urethral valves. In the past, damaged organs have been replaced with autologous and allogenic tissues. While both of these solutions have enabled patients to lead more normal lives, both are fraught with potential complications inherent in the donated tissue. For example, urinary diversion with intestine may have sequential electrolyte abnormalities, and renal transplantation may lead to multiple complications associated with immunosuppression. The field of regenerative medicine stems from the desire to create replacement tissues, for patients whose own tissues are deficient, with functionally and physiologically equivalent tissues that are not subject to rejection by the body’s immune system.