Holding infants — or not — can leave traces on their genes

The amount of physical contact between infants and their caregivers can affect children at the molecular level. The study of DNA methylation patterns showed that children who had been more distressed as infants and had received less physical contact had a molecular profile that was underdeveloped for their age. This is the first study to show in humans that the simple act of touching, early in life, has deeply-rooted and potentially lifelong consequences on genetic expression.