In order to clarify the role of sex chromosome constitution in craniofacial growth control, we compared craniofacial morphology of men with sex reversal syndrome (46, XX) with the morphology of normal men, Klinefelter's syndrome and normal women, using cephalometric measurements. Due to physical resemblance between men with 46, XX karyotype and men with 47, XXY karyotype, cephalometric analysis comprised parametres which had already been found to be specific for Klinefelter's syndrome, i.e. cranial base length and flexion, maxillary and mandibular base length, jaw position in relation to cranial base and sagittal jaw relationship. Linear measurements showed reduction of about 10% in maxillary base length in 46, XX men in relation to normal men. Mandibular base in men with sex reversal syndrome was also shortened for about 10% in relation to both normal men and Klinefelter's syndrome. Cranial base flexion in men with Klinefelter's syndrome and in men with sex reversal syndrome showed similarity. The basal angle was found to be more acute, for about 4 degrees , in comparison to individuals with normal karyotype. Unlike in men with Klinefelter's syndrome, mandibular and maxillary prognathism were not registered in men with sex reversal syndrome.