Marriages Between the Deaf and Hereditary Deafness in Finland

Abstract

According to the 1950 population census, Finland has 130.7 deaf per 100,000 inhabitants, which must be regarded as quite a high figure. A study was conducted in 1961-1965 of marriages between two deaf persons. They totalled 556 in June 1961, and 554 of them were covered by this study. The 554 marriages between deaf partners produced 1126 children, an average of 2.2 per marriage. This is appreciably lower than the general level in the country. Childless marriages accounted for 17 per cent. Of the children born of the marriages, 4.6 per cent were deaf. To establish genetic deafness, a family tree was compiled for each proband in the material. It extended backward to at least the third generation and included the children of the probands. Rosin's statistical method was used to test the genealogical analysis. The genetic analysis revealed that 52 per cent of the isolated cases were genetic.