AbstractA specimen of human symmelia was judged at first to be a male from the appearance and disposition of the pelvic viscera but histological study of the gonads later showed that it was a female. This raises the question of whether the preponderance of males with this abnormality might be explained, at least in part, by incorrect diagnosis of sex particularly where this has been based on gross appearances. The bladder, rectum, anus, and external genitalia were missing and the kidneys were replaced by a mass of renal tissue dorsal to the lower aorta. There was a single umbilical arrery which was identified as a persistent left primary umbilical artery. Within the lower limb were two femora, two tibiae, and one fibula. Secondary centers of ossification were present in the distal ends of the femora and the proximal ends of the tibiae.