Previous studies have suggested that children with neurofibromatosis type 1 (NF1) are shorter than their unaffected counterparts. Unfortunately, these reports did not consider other contributing factors that might also influence short stature. The purpose of the current study was to characterize the genetic influence of NF1 on the growth of children. Height data were measured and recorded for 170 patients, whereas parental measurements were obtained for 61 patients to calculate sex-corrected mid-parental target heights. Children with NF1 had population mean height and mid-parental height z scores statistically different from the general population. Importantly, these differences were pronounced when neither parent had NF1 but were not significant when one of the parents had NF1. Moreover, height z scores for children with NF1 were also statistically different than their unaffected siblings. Collectively, these data establish a clear effect of a germline NF1 gene mutation on stature in children with NF1.