Klinefelter's syndrome is a genetically transmitted endocrinological disorder characterized by a complement of 44 autosomes with an XXY sex-chromosome complex; it is frequently accompanied by neuropsychiatric disorders, although childhood schizophrenia has not been previously reported. Noting a statistically significant increase in the incidence of Klinefelter's syndrome in a schizophrenic population, the authors advance several verifiable hypotheses: adult Klinefelter schizophrenics may have psychotic processes of early origin, a high percentage of children currently diagnosed as psychotic may have Klinefelter's syndrome, and those with Klinefelter's syndrome may have increased susceptibility to develop schizophrenia.Abstract Teaser