Levels of testosterone-estradiol binding globulin (TeBG) were measured by a precipitation technique in terms of dihydrotestosterone-5.alpha. (DHT) binding capacity in children, adult males and females, pregnant and hirsute women and women with various trophoblastic disorders. TeBG levels in children of either sex (1.92 .+-. 0.16 .mu.g DHT bound/100 ml serum) approached the normal female range (2.31 .+-. 0.11) and were distinctly higher than those of the adult male (1.04 .+-. 0.09). In both pregnancy and trophoblastic disease (hydatidiform mole and choriocarcinoma but mot metastatic choriorcarcinoma) TeBG levels were elevated (17.5 .+-. 0.70 and 14.9 .+-. 1.49, respectively). In hirsutism TeBG was depressed (1.17 .+-. 0.09) and comparable with the levels in normal male subjects. A number of other parameters, HCG [human chorionic gonadotropin] estradiol-17.beta., testosterone and progesterone were measured and were similar to those previously reported in the literature. TeBG titer might provide an additional index in following the prognosis of trophoblastic disorders, besides HCG measurement.