There has been a study by the University of British Columbia in Canada that when a baby is not cuddled or given much physical touch their gene expression can be affected. This is a very new study, so it still is not clear what exactly is causing the gene expression to change. During the study, the parents were asked to keep track of their cuddling with their babies and after four and a half years later their DNA was sampled. In the samples, the children who had low contact had differences in DNA methylation at five different sites. There was also a difference in epigenetic ageing that was different from their actual age. There needs to be more studies done to actual identify what exactly about not receiving physical touch causes genetic expression changes.