The age at which boys begin puberty is linked to when their mothers started having periods, a study suggests.
Mothers who started earlier than their peers have sons who had: armpit hair two and a half months earlier; acne and voices breaking two months earlier. Their daughters develop breasts six months earlier BBC reports.
The study’s authors S Sørensen N Brix A Ernst L L B Lauridsen C H Ramlau-Hansen analysed data from nearly 16,000 Danish mothers and children.
Results were published in the Human Reproduction journal.
Whenever a doctor meets a patient with delayed or early onset of puberty, the doctor obtains a family history, comments One of the authors, Dr Nis Brix, of Aarhus University, Denmark.
The age boys and girls start puberty has been gradually decreasing around the world. In the UK, it is currently starting about one month earlier every decade.
And the current average age is: 11 for girls and 12 for boys.
Experts put this down to improved health and nutrition in the industrialised world - but studies have also shown a link between obesity and the early onset of puberty.
Early maternal age at menarche was associated with earlier pubertal development, and late maternal age at menarche was associated with later pubertal development in both sons and daughters. The largest effect-estimates were for the associations between maternal age at menarche and the daughters’ age at menarche and age at breast development.