Birth stress and lateral preferences.

Conflicting evidence exists concerning the possible role of birth stress in the etiology of left-sided lateral preferences. In order to clarify this issue, associations among lateral preferences of hand, eye, and foot and eight indices of prenatal and perinatal stress were examined in the present study on a sample of 987 boys and girls who participated in the Philadelphia Collaborative Perinatal Project. Controls were instituted for some of the methodological and measurement problems encountered in past birth stress and laterality research. Results showed that subjects with different lateral preferences did not differ significantly in their distributions of all but one birth stress items. Hence, there was no substantial evidence for a link between birth stress and left-sided preferences. Alternative hypotheses for the etiology of left-sidedness should therefore be explored.