Many things have changed since the arrival of humanity’s first species. New research shows that men have always been more likely to become parents later than women in human history.
Scientists at Indiana University, Bloomington in the US conducted a study to determine when women and men have had babies in the last 250,000 years since the emergence of our species.
They used data to track the age at conception and DNA mutations for three generations of 1,500 Icelanders. This model was first used on a sample of 2,500 people around the globe. Then, they dated back the emergence and progression of different mutations to create an age-based timeline of motherhood as well as fatherhood.
They discovered that dads became fathers at 30.7 and women at 23.2, respectively, over the millennia. That means that throughout history, men discovered the joys and pains of parenthood a staggering seven years later than women (whether they took – and now take – an active role in parenting is debatable, of course).
These findings were published in Science Advances.
Previous studies They also found that parents are more likely to be men than women. However, their findings were limited to the past 400,00 years. It is difficult to determine when people had children in distant history. However, scientists can track down that information using mutations that spontaneously occur between generations.
These mutations do not occur between parents or children. They are caused by DNA damage that occurs before conception. Recent research suggests that older parents may pass more mutations to their children than younger ones.
Watch the biological clock ticking
What is the reason that men become fathers later than women?
“The longer generation times for men can be generally explained by the fact that men are biologically able to have children later in life than women, bringing up the average age of fatherhood”, lead researcher Richard Wang said in the journal Nature.
But the answer is not that simple, because the infamous ‘biological clock’ which women are told starts ticking as they approach the age of 30 is not the only factor to consider.
Wang and his collaborators wrote that the average age at birth for people – men and women – is affected by many factors. These factors include cultural and environmental factors.
Mikkel Schierup, a population geneticist from Aarhus University in Denmark, said that the findings could also indicate social factors, such as the pressure on patriarchal societies’ men to achieve status before they become fathers.
There are other factors that have contributed to the rise in the number of children born to women today. The World Population Review states that on average, women have their first child at 28. Some women have their first child in their 40s in Western countries, as well as other nations where women can pursue a career.
The team at Indiana University acknowledged this trend, with Wang and his colleagues writing that they have reported “a substantial increase in female generation times in the recent past”.
But as the average age of mothers is changing, it’s also likely that that of fathers is gradually rising too. Only time will reveal if dads will always be older than moms.
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