Infants who take longer to learn to walk may end up doing better at school, a genetic study suggests.
Scientists discovered the age at which babies take their first steps is strongly influenced by their genes.
They also found that the same genes that are linked to late walking are also involved in higher educational achievement.
It suggests the same genes that predispose youngsters to do well in education may also be influencing when babies start to walk.
Late walking also appears to lower the risk of ADHD (attention deficit hyperactivity disorder).
The study from the universities of Surrey, Essex and London found that genetics accounts for about a quarter of the differences in when children take their first steps.
‘First genetic study of infant behaviour at this scale’
“We studied hundreds of thousands of genetic differences that are common in the population,” said Angelica Ronald, professor of psychology and genetics at the University of Surrey.
“We see that the genetic differences that influence walking later also influence higher educational attainment and less likelihood of ADHD.
“It is the first genetic study of infant behaviour at this scale and the first one to investigate when children learn to walk.
“Genetic differences are important to study because they teach us about the biology underlying these behaviours.”
Babies generally take their first steps sometime between ages eight and 24 months, with most toddlers walking unaided by 18 months. But this can vary and parents often worry if their children take longer to hit the important developmental milestone.
For years, researchers knew environmental factors could influence when babies begin to walk, but this new finding shows genetics also has a major impact.
In the first study of its kind, scientists analysed the genetic information of more than 70,000 infants, identifying 11 genetic markers influencing when babies start walking.
The team found that genetic factors responsible for the timing of a child’s first steps are also linked to brain development, including the amount of folding and ridges in the outer surface of the brain - the cortex.
Relatively later onset of walking was influenced by some of the same genes involved in higher educational attainment.
Likewise, walking later was linked genetically to a lower chance of developing ADHD.
Dr Anna Gui, an author of the study and a researcher at the University of Rome Tor Vergata and Birkbeck, University of London said: “Until now, we didn’t understand what causes the wide differences between children when they take their first step.
“Parents might often worry that walking early or late is a bad sign or that they have done something wrong. We see that genetics play a considerable role in influencing the timing of this milestone.”
Other factors that influence when a baby will begin walking include the strength of leg muscles, general health and opportunities for practising
Prof Ronald added: “While parents should still see their GP if they are concerned, a slightly later start is not always a sign of problems. There is a lot of variety when children take their first step on their own.
“It is exciting to be able to discover the genes that influence when children learn to walk. Starting to walk independently is a major milestone for young children.”
The research was published in the journal Nature Human Behaviour.