It is well known that the majority of young children who are profoundly deaf are stated to have been born deaf, and it has long been accepted that this presumed congenital deafness is often hereditary. Before the development of the modern views on modes of inheritance teachers and other persons in contact with the so-called deaf mutes noted that in certain families the defect appeared generation after generation and that in others it frequently occurred among the offspring of consanguineous marriages (Bell1; Fay2). In recent years otologists familiar with genetic analysis have, from the study of a limited number of pedigrees, arrived at the conclusion that this form of profound deafness is transmitted according to a simple mendelian scheme (Albrecht3; Ciocco and associates4). The implications of such a conclusion and its importance viewed either from a broad public health standpoint or from the position of the otologist whose advice is