Percentiles of birth weight are important tool for correct diagnosis of hypotrophy. Percentile curves, derived from newborns of the GDR, consider only the infant's sex. Parity and parental physical characteristics have essential influence on the weight of the newborn infant. The dignity of anthropometric characteristics and the parity for the birth weight are investigated based on 10.800 cases. A correlation formula has been developed for a precise assessment of the infant's position in relation to the percentile standards. Nomograms are suggested, making corrections for parental stature.