[French and German summ.][long dash]The Gc-types in 95 Norwegian families with 343 children were determined. Only one apparent exception from the postulated mode of inheritance of the Gc-types was observed, namely a child whose extramarital status was demonstrated by other blood group constellations. The observed frequencies of the different Gc-types were in good accordance with expectation. The reproducibility of Gc-typing was demonstrated by the fact that duplicate tests always gave identical results. The usefulness of the system in cases of disputed paternity is briefly discussed.