Whether babies take their first steps at nine or 15 months depends on a lot of factors – including their genes, a new study has found.
New parents wait with bated breath for their babies to begin walking independently, which is an important early sign of child development.
But the exact age that they start hinges on their size, whether they were born early, if they’ve had the chance to practice walking, and their nutrition, among other conditions.
Now, the study indicates 11 genetic markers can explain about a quarter of the variation in when babies start walking on their own.
“Parents can provide a constructive environment and support their children, but they’re not 100 per cent in control,” Angelica Ronald, the study’s senior author and a professor of psychology and genetics at the University of Surrey in the UK, told Euronews Health.
“Genes also influence this timing”.
The study was published in the journal Nature Human Behaviour and included nearly 71,000 children in Norway, the Netherlands, and the UK.
The genes that influence the age at which children learn to walk overlap closely with genes that affect both brain size and how many folds are on the outer layer of the brain, which is associated with cognitive function, the analysis found.
Notably, the genes tied to early walking also overlap with those linked to attention deficit hyperactivity disorder (ADHD).
The researchers hypothesised that more active babies with shorter attention spans could move around more, giving them more practice walking earlier.
Meanwhile other research has shown that learning how to walk late – beyond around 18 months – can be an early sign of intellectual disabilities.
The new findings “suggest that the genes influencing the age of onset of walking are quite central to development across a range of areas,” Ronald said.
Going forward, Roland’s team plans to study how genes interact with the environment to shape young children’s development, with the goal of identifying the most ideal settings for infants to grow up.
But for now, she said the results should help assuage parents’ worries that they aren’t doing enough to help their babies walk unassisted.
“We put a lot of emphasis on kids who do things quicker than others,” Ronald said, but “there are probably advantages to walking later and walking earlier”.