New European research has found that the age at which a woman starts her periods appears to be linked to the age at which her son will start puberty.
Carried out by researchers at Aarhus University, Denmark, the study, published in the journal Human Reproduction, is the largest so far to investigate the association between a mother’s first period and the age puberty starts in both sons and daughters.
Although previous studies have shown that the age at which women experience their first period is largely inherited from mother to daughter, so far it has remained unclear as to what association there may be with the timing of puberty in sons.
For the new study the researchers looked at 15,822 children born between 2000 and 2003 and followed them until 2016. From the age of 11 the children were asked to complete questionnaires every six months, which included questions on puberty, while mothers were asked about the age when they had their first menstrual bleed.
The findings showed that the earlier women had their first period, the earlier their sons started puberty, and the later they had their first period, the later their sons started puberty.
In line with previous studies, the same association was also found for daughters.
“We found that mothers who reported having their first menstrual bleed earlier than their peers had sons with signs of puberty starting earlier than their peers,” commented one of the study authors, Dr. Nis Brix. “The largest difference was when hair started growing in the armpits, which started, on average, approximately two and a half months earlier; their voices broke nearly two months earlier, acne started to develop nearly two months earlier and their first ejaculation of semen was nearly one and a half months earlier. If their mothers started puberty later than their peers, then the sons experienced first ejaculation, growth of armpit hair and acne development later than their peers.”
Over the last 100 years, the timing of puberty has gradually started earlier, probably due to better health and living standards. However, a younger age at puberty has also been linked to increased risk of diseases later in life, such as breast and testicular cancer, diabetes and cardiovascular disease.