Association between parental age at childbirth and timing of puberty in children: an 8-year cohort study

Abstract Background The timing of puberty in offspring is influenced by various factors, including genetics and environment. While some studies suggest a link between parental age at childbirth and pubertal timing, the evidence remains inconsistent. This study aimed to investigate the association between parental age at reproduction and the timing of pubertal development events in their sons and daughters. Methods We conducted a prospective cohort study with 1,386 children (51.7% girls) followed for a median of 7.00 years. Parental age was collected retrospectively. Pubertal development, including genital, breast, and pubic hair growth, as well as spermarche and menarche, was assessed semiannually. Accelerated Failure Time-Restrictive Cubic Spline models were used to analyze the impact of paternal and maternal age on the timing of these pubertal events. Results Advanced maternal age at childbirth was significantly associated with an earlier age at spermarche in boys (P < 0.05). A non-linear association was also observed between maternal age at childbirth and the timing of genital development (P = 0.01). Both maternal and paternal ages at childbirth were significantly associated with the timing of breast and axillary hair development onset in girls in a non-linear, inverse U-shaped manner (P = 0.02 and P < 0.01, respectively), indicating that both younger and older parental ages are linked to the earlier breast and axillary hair development. Conclusions This study suggests that parental age at childbirth is associated with pubertal development in offspring, including the timing of spermarche and genital development in boys and the onset of breast and axillary hair development in girls. Specifically, both younger and older parental ages have been linked to earlier attainment of these pubertal milestones, particularly among girls. In summary, the study showed that the specific pubertal events affected by parental age and the nature of that association were different for boys and girls. Plain english summary The timing of puberty can affect a child’s future health. The aim of this study was to investigate whether a parent’s age at the time of childbirth influences when their child enters puberty. We conducted a long-term (with a median duration of 7 years) follow-up study on 1386 children to track their pubertal development. We found that the effects of parental age differ between boys and girls. For boys, having an older mother at birth was linked to reaching spermarche (first ejaculation) at a younger age. For girls, the findings were more complex. Both younger and older parental ages were linked to earlier breast and underarm hair development. This U-shaped pattern means that girls born to very young or very old parents tended to show these signs of puberty sooner than those born to parents in the middle-age range. In short, this study suggests that a parent’s age does play a role in the timing of their child’s puberty, but the effects are different for boys and girls. This information can help parents and doctors better understand the factors influencing child development. Highlights 1. Advanced Maternal Age and Earlier Puberty in Sons: Older maternal age at childbirth was significantly linked to boys reaching spermarche (first ejaculation) at a younger age 2. A U-Shaped Association for Daughters: For girls, both younger and older parental ages at childbirth were associated with an earlier onset of breast and underarm hair development 3. Gender-Specific Effects: The study highlights that the impact of parental age on puberty is different for boys and girls, affecting distinct pubertal milestones in a non-uniform pattern