Earedness and handedness: Distribution in a German sample with some familydata

There are only few data on the relative contribution of genetical factors t o ear preference ("earedness"). We studied the distribution of earedness an d handedness in a sample of 292 families and 36 offspring pairs. The incide nce of nonright-earedness was found to be 35% and was not related to age or gender. In the same sample the incidence of nonright-handedness amounted t o about 9% and was characterized by a significant prevalence in men. The di stribution of handedness did not differ significantly between parents and c hildren. We found that children's earedness and handedness were related to parental preferences. However, no paternal or maternal effect was found. Th e frequency of left-earedness and left-handedness of children is directly p roportional to the number of left-sided parents. These results suggest that the direction of ear preference and handedness is genetically determined. But there is no genetic association between handedness and earedness.