Penile agenesis is a very uncommon birth defect in humans. It is estimated to occur once every 5-10 million births and is characterized by the absence of a penis at birth in the male child.A partner can be afflicted by testicular or penile agenesis. This is a condition in which a male child is born without gonads and does not develop testicles as a result. Leydig cells are responsible for the transformation of the gonads into the testicles and ovaries of the adult male and female, respectively, in the growing embryo. The method is not successful in certain instances.