medwireNews: The timing of puberty in children is influenced by that of their fathers, as well as their mothers, a study shows.

If fathers reported maturing earlier or later than their peers, this had a significant effect on the timing of all pubertal milestones in boys and most of those in girls.

For example, boys developed pubic hair an average of 11.8 months earlier if their fathers were early-maturing than if they were late-maturing, but an average of 6.4 months later if their fathers matured late rather than in line with their peers. The timing of fathers’ puberty had similar effects on the timing of gonadarche (testicular volume >3 mL) and reaching Tanner genital stage 2.

Among girls, fathers’ pubertal timing had significant effects on the timing of pubic hair development and menarche, but had only marginal effects on the timing of breast development, with late but not early paternal maturation influencing thelarche timing.

The study, which appears in The Journal of Clinical Endocrinology & Metabolism, included 672 girls and 846 boys, and their parents. The children underwent annual physical examinations, while the parents’ pubertal timing was assessed by questionnaire.

Mothers’ pubertal timing and their recalled age at menarche affected almost every aspect of the pubertal timing of both boys and girls.

For example, boys with early-maturing mothers (vs late) developed pubic hair an average of 8.0 months earlier, while those with late-maturing mothers (vs average) developed it an average of 7.2 months later.

Mothers’ age at menarche had the largest impact on their daughters’ age at menarche, with each additional year in the mothers’ age being associated with a 4.4-month increase in that of their daughters. Other pubertal milestones in girls and boys were less affected by their mothers’ age at menarche, with increases ranging from a nonsignificant 1.0 months for pubic hair in girls to a significant 2.4 months for pubic hair in boys.

Overall, parental pubertal timing explained up to 9.3% of the variation of pubertal timing in boys and up to 14.5% of that in girls. The milestone with the least parental influence was breast development in girls, with parental pubertal timing accounting for just 3.3% of the variance.

Christine Wohlfahrt-Veje (University of Copenhagen, Denmark) and study co-authors note that, in line with previous research, children reached most pubertal milestones earlier than those in older studies, and the girls reached menarche at a significantly younger age than their mothers did.

“This is in line with the hypothesis that the observed trend towards earlier pubertal maturation is not caused by genetics, but most probably other (environmental) factors”, they say.

By Eleanor McDermid

J Clin Endocrinol Metab 2016; Advance online publication

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