The H. N. Handedness Inventory and a disease questionnaire were administered to a sample of 1700 undergraduate students. There was no significant relation between handedness and report of any immune disorders surveyed. The incidence of stuttering was higher in non-right-handers than in right-handers. The data provide partial support for Geschwind and Galaburda's testosterone hypothesis that links left-handedness to learning disorders, but not to immune disorders.