A mother's touch is often said to be crucial in helping her bond with her child, but new research suggests babies may even be able to recognise it while still in the womb.
Unborn infants have been recorded reaching out to touch the wall of the uterus in response to their mother caressing her bump during pregnancy.
Using three-dimensional ultrasound videos, scientists were able to watch how unborn children reacted to different people touching their mother's abdomen, reports Daily Mail.
The strongest response came when a mother rubbed her own stomach compared to when a stranger or the child's father did, suggesting the infant recognised who was involved.
It may also explain why mothers often feel their babies moving when they touch their stomach but someone else might not detect any motion.
Dr Viola Marx, a psychologist at the University of Dundee, was the lead author of the study, published in the journal Infant Behaviour And Development.
She said: "Mothers spontaneously and also intentionally touch their abdomen during pregnancy, often to communicate with the foetus.
"Any stimulation can be beneficial to the development of the foetus and bonding of the mother, father and the foetus."
Oddly, the unborn babies responded more to a stranger's touch than their father's.
Dr Marx said previous research had shown unborn babies also respond when their mother talks to them, helping them recognise her voice after birth.