Letter: Birth order and left-handedness.

Abstract

Bakan 1 proposed the hypothesis that left-handedness is associated with stressful prenatal and birth conditions. He equated first and fourth or higher birth order with greater stress than second and third birth order. In male university students, he found that first or fourth and higher birth order was acknowledged more commonly by left-handers than by right-handers. In females, however, the differences in birth order between left- and right-handers were smaller. However, Hubbard, 2 in his study of university students of both sexes, found that right-handers rather than left-handers had the higher frequency of first or fourth and higher birth order. To resolve this discrepancy, 488 sixth-grade students and their 104 fifth-grade-age peers, who would have been in the sixth grade had they not repeated a grade, were questioned about birth order (How many older brothers and sisters do you have?) and about five measures of handedness (With which hand do