It has been known for some time that the mothers’ age at puberty is associated with their daughters’, but much less is known about how it affects their sons.

New research has found 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. The same can be said for daughters, the study added. Although better health and living standards may have advanced the time of puberty in sons and daughters over the past century, early onset may also mean increasing the risk of diseases in later adult life, such as breast and testicular cancer, diabetes and cardiovascular disease.

Additionally, girls who mature earlier than their peers are known to show signs of depression, and boys initially have lower levels of depression than later-maturing boys, but over-time show signs of increased anxiety, negative self-image and interpersonal stress.

An overlap in the genes could be causing an advancement in puberty, said authors.

To study it further, researchers based out of Aarhus University in Denmark investigated 15,822 children born between 2000 and 2003 and studied them until 2016. During this time, they also interviewed the mothers twice during pregnancy and asked them to fill in a questionnaire when the children were seven. While the mothers were asked about how old they were when they had their first period, the children were asked to complete questionnaires that included questions on puberty every six months from the time they turned 11.

“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,” said 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,” Dr Brix added.

Similar results were observed in daughters. The largest difference was seen in breast development, which started up to six months earlier in girls whose mothers had experienced earlier periods than their peers, or up to four months later in girls whose mothers had started puberty later than their peers.

Similar studies earlier have always researched the relationship between first menstrual bleeding in mothers and the same in their daughters, but Dr Brix said, their study was different since they included other markers of pubertal development such as different stages of breast and pubic hair development.

Dr Briz said, “We already knew (the relationship between the mothers’ first menstrual bleed and its impact on their children’s puberty) it, but now we have the results to confirm it.”

Therefore, it might be the best to keep a watch on both, sons and daughters, in case they’ve hit puberty earlier than usual to avoid them from showing behavioral problems. Experts also advise watching for early sexual activity because with early puberty, they are likelier to be sexually active at a younger age. Additionally, it can be a stressful time for children, they might feel awkward about looking different from their friends, so you might want to help educating them about the kind of changes they should expect to avoid being taken in for a surprise.