Relations between a dermatoglyphic measure, hemispheric specialization, and intellectual abilities in 47,XXY males

Verbal IQ is usually lower than performance IQ in neonatally identified 47,XXY males. A dermatoglyphic measure reflecting prenatal growth rates and indices of sex-related hormonal functioning are also frequently abnormal in 47,XXY males. This paper presents evidence indicating that a measure of prenatal growth rate predicts right hemispheric specialization for nonverbal processing in extra X males, whereas levels of testosterone, estradiol, luteinizing hormone, and follicle-stimulating hormones do not. Findings are also reported which indicate that the low verbal IQs of 47,XXY males are the result of abnormalities in right hemispheric functioning.