How Genes Influence the Timing of a Baby's First Step

When a baby takes their first step unaided, it is a big moment for parents and their baby. After all, it symbolises a new phase in a child’s life. They officially, and literally, become a ‘toddler.’ Once walking, infants gain more independence and a wider visual perspective. But what influences the timing of this important milestone?

Traditionally, research has focused on environmental factors to answer this question. Research has pointed to nutrition, culture, and practice, amongst other things. After all, it takes many attempts before a child can walk unaided. They fall over a lot before the first unsupported step happens.

In our work, we were interested in whether genetics played a role, and if so, which genes were involved and what they did (Ronald and Gui, 2024).

In their DNA

In our study, we analysed data from over 70,000 infants (Gui and colleagues, 2025). We found that a quarter of the differences between babies, when they take their first unsupported step, are due to the genetic influences we studied.

We discovered that the genes influencing walking onset are expressed in the brain. They influence the size of the motor regions of the brain, and they influence the degree of folding of the outer surface of the brain (the cortex).

These same genes that influence walking onset also influence the likelihood of developing ADHD and educational success. Thus, the genes involved in influencing children's learning to walk appear to play an important role in brain development and in affecting later outcomes as well.

We observed that if some of these genes don’t work well, this might cause developmental delay. For example, children with rare genetic syndromes that involve some of the same genes that we discovered have low muscle tone and delayed or absent walking.

How does this change things?

The best way to understand the timing of walking onset is to consider it as something that shows wide variation between children and is influenced by genetics and environment. Thus, it is unlikely that parents can completely control when their child takes their first step, because this will be partly due to their genetics. Our study shows that children who have a genetic predisposition to walk later might also be genetically predisposed to stay in education for longer and have a lower likelihood of having ADHD. However, environments such as nutrition and space to practice moving are also vital for children’s motor development, such as walking.

Now that we have discovered the genes, the next steps for us as scientists are to understand more precisely what the genes do in the brain, and understand how genes work with environments to affect child development.

If you are a parent concerned about when your child will walk, speak to your pediatrician. Bear in mind that it is common for children to differ widely in when they first take their independent step. When the time comes, be sure to have your camera ready!

Angelica Ronald is Professor of Psychology and Genetics in the School of Psychology at the University of Surrey. Anna Gui is a researcher at the University of Rome Tor Vergata.