The timing of sexual maturation in a group of US white youths.

The purpose of this study was to present US reference data for chronological ages at which stages of sexual maturation were observed in white youths. Recent serial data from 78 males and 67 females were analyzed to obtain descriptive statistics for the ages at onset of these stages and the mean ages at which the stages are observed. These reference data should assist the identification of white US youths who are maturing at rapid or slow rates and the interpretation of growth data.