Abstract: Hypohidrotic ectodermal dysplasia (HED) is a welldescribed, X-linked recessive disorder characterized by hypohidrosis, hypodontia, and hypotrichosis in males. Reports of similarly affected females have suggested autosomal recessive inheritance in some families. The evidence for two clinically identical but genetically distinct disorders is not convincing, however. In two families with X-linked recessive inheritance of HED, the condition was severe in females. A critical review of previously reported cases of presumed autosomal recessive HED suggests that an autosomal recessive form of the condition identical to the X-linked HED may not exist. All sporadic instances of females with classic HED should be considered to be X-linked recessive, and counseling for X-linked recessive inheritance as well as autosomal recessive inheritance should be given.