Thirty dyslexic and 30 control boys aged 7-11 years were compared for frequency of immune disorders and handedness as well as for family history of immune disorders and learning disabilities (dyslexia and stuttering). They were also compared for neurological status and for history of speech and language difficulties. There were no significant differences between the two groups in the frequency of immune disorders and in handedness. The results showed significantly more dyslexic boys with soft neurological signs and signs of speech and language disorders. The frequency of dyslexia was significantly higher in the relatives of the dyslexic boys. Also significantly more mothers of the dyslexic boys reported difficulties during pregnancy and complications at delivery. The results are discussed in terms of Geschwind's hypothesis and neuromaturational delay as possible determinants of developmental dyslexia.