Earedness and handedness: distribution in a German sample with some family data.

There are only few data on the relative contribution of genetical factors to ear preference ("earedness"). We studied the distribution of earedness and handedness in a sample of 292 families and 36 offspring pairs. The incidence 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 to about 9% and was characterized by a significant prevalence in men. The distribution of handedness did not differ significantly between parents and children. We found that children's earedness and handedness were related to parental preferences. However, no paternal or maternal effect was found. The frequency of left-earedness and left-handedness of children is directly proportional 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.