Sex chromosome and chromatin examinations with hormone determinations were done on 41 cases seen at the gynecologic clinic suspected of having sexual developmental abnormalities. 22 (53.7%) had genetic, gonadal or hormonal abnormalities, including ovarian dysgenesis 9 cases, superfemale 1 case, XY pure gonadal dysgenesis 4 cases, 3 of whom had already developed gonadal malignancy, pseudovaginal perineoscrotal hypospadias 1 case, androgen insensitivity syndrome 2 cases and congenital adrenal hyperplasia 3 cases. The values and limitations of sex chromosome and chromatin examinations as well as the prevention of gonadal malignancy are discussed.