The present study examines the relationship between femur length and stature in children between the ages of 8 and 18 years. In previous investigations, my colleagues and I reported the surprising finding that femur length bears a nearly constant relationship to stature in adult humans regardless of ethnicity or gender. This earlier study revealed that the femur/stature ratio averages 26.74% in adult humans, and that using the ratio to predict stature from femur length yields remarkably accurate estimates. The current study shows that femur/stature ratios of children between the ages of 8 and 11 differ significantly from their older counterparts. Between the ages of 12 and 18, there are no significant differences due to age in the femur/stature ratio; however, there are significant differences in this age group attributable to gender. This study also shows that the worldwide average adult femur/stature ratio does not adequately describe children in this age range. This study strongly documents the adolescent growth spurt in the femur/stature ratios of both males and females at the precise time one would expect to see the spurt occur (10-12 in females; 12-14 in males). This growth follows a nearly identical trajectory in both genders, with relative femur growth dominating before the peak years of the growth spurt, and relative stature growth dominating afterward. This accounts for the ratio's rise to maximum values just before peak growth, and its decline toward the adult ratio thereafter. These findings require us to use separate adolescent femur/stature ratios of 27.16 (females) and 27.44 (males) to estimate the stature of children between the ages of 12 and 18. Preliminary testing shows these ratios to be more accurate in estimating stature than the properly selected Trotter and Gleser adult regression equation. Use of the adolescent male ratio with the Homo erectus juvenile WT 15000 results in a lower stature estimate (157.4 cm) than previously reported. It is suggested that continued testing of the ratio occur, but that the values herein derived may be useful in routine forensic cases involving children in this age range, and with subadult paleontological specimens.