Pubertal Onset in Boys and Girls Is Influenced by Pubertal Timing of Both Parents.

CONTEXT: Epidemiological evidence on maternal and paternal heritability of the wide normal variation within pubertal timing is sparse.

OBJECTIVE: We aimed to estimate the impact of parental pubertal timing on the onset of puberty in boys and girls.

DESIGN: Annual pubertal examinations of healthy children in a longitudinal cohort study. Information on parental timing of puberty (earlier, comparable to, or later compared to peers) and menarche age was retrieved from questionnaires.

PARTICIPANTS: A total of 672 girls and 846 boys.

MAIN OUTCOME MEASURES: Age at onset of pubic hair (PH2+), breasts (B2+), and menarche in girls; and PH2+, genital stage (G2+), and testis >3 mL with orchidometer (Tvol3+) in boys.

RESULTS: In boys, pubertal onset was significantly associated with pubertal timing of both parents. PH2+ and Tvol3+ were earlier: -11.8 months (95% confidence interval, -16.8, -6.8)/-8.9 (-12.8, -4.9), and -9.5 (-13.9, -5.1)/-7.1 (-10.4, -3.7) if the father/mother, respectively, had early pubertal development compared to late. In girls, menarche was significantly associated with both parents' pubertal timing: -10.5 months (-15.9, -5.1)/-10.1 (-14.3, -6.0) if father/mother had early pubertal development compared to late. For the onset of PH2+ and B2+ in girls, estimates were -7.0 months (-12.6, -1.4) and -4.1 (-10.6, +2.4)/-6.7 (-11.0, -2.5), and -6.7 (-11.0, -2.0) for fathers/mothers, respectively. Maternal age of menarche was significantly associated with the onset of all pubertal milestones except PH2+ in girls.

CONCLUSIONS: Maternal as well as paternal pubertal timing was a strong determinant of age at pubertal onset in both girls and boys. Age at breast and pubic hair development in girls, which has declined most during recent years, seemed to be least dependent on heritability.