Left-handedness and life span: A reply to Harris.

Abstract

L. G. Harris's (1993) critique of our hypothesis that left-handedness is associated with a shorter life span (S. Coren & D. F. Halpern, 1991) ignores the supporting statistical evidence, which virtually always shows an increased incidence of left handedness (or other left-sided laterality) associated with a wide range of health risk factors, including serious accidents, immune disorders, early onset breast cancer, alcoholism, smoking, some types of mental retardation, homosexuality, birth-related complications (e.g., resuscitation at birth, extremely low birth weight, Rh incompatibilities, multiple birth, breechbirth, and older maternal age), and selected categories of mental disorders