Feeling broody? You must be about 27, say scientists

Study of DNA mutations throughout history reveals when people are most likely to have children

‘The results show that human generation times have undergone a rapid increase in the recent past’

WHILE there may never be a “perfect moment” to start a family, scientists have revealed that, since the dawn of our species, 27 is the age when people are most likely to start to have children.

Homo sapiens emerged as a species in Africa around 300,000 years ago and scientists at Indiana University used DNA mutations to track when a new generation was made for the past 250,000 years.

“Through our research on modern humans, we noticed that we could predict the age at which people had children from the types of DNA mutations they left to their children,” said Prof Matthew Hahn, the study co-author.

“We then applied this model to our human ancestors to determine what age our ancestors procreated.”

Every child inherits half their DNA from their mother and half from their father, but they also gain around 25 to 75 new mutations each.

Analysis of thousands of samples showed that the types and kinds of mutations a child gets from their parents depends on the age at which the parents were when they procreated. DNA analysis found that, on average, humans had children aged 26.9 years old. The average was 31 years old for men and 23 for women, data indicate.

Over the past 100 generations, the average length of a generation has increased sharply towards 30, with the average maternal age now being 26.4 years old.

They add that over the course of recent history, the average age of parents was at its youngest (25 years old) around 6,400 years ago, when civilisations first began.

“The results show that human generation times have undergone a rapid increase in the recent past after declining for over a thousand generations,” the researchers write in their study, published in Science Advances.

“The average human generation interval was at a recent minimum of 24.9 years about 250 generations ago [6,400 years ago], roughly concurrent with the rise of early civilisations. Before this, it had declined from a peak of 29.8 years 1,400 generations ago (38,000 years ago), just before the beginning of the last glacial maximum.”

The analysis also found that men have always been older than women when it comes to having children.

“The findings from our genetic analysis confirm some things we knew from other sources, but also offer a richer understanding of the demography of ancient humans,” Dr Richard Wang,