Few studies have used the baby's cry as a means of evaluating the quality of neonatal care. In this randomized trial the newborn's cry was registered during the first 90 min after birth when infants were cared for either: (a) skin-to-skin with the mother; (b) in a cot; or (c) in a cot for the first 45 min of the 90-min observation period and then skin-to-skin with the mother. The results suggested that human infants recognize physical separation from their mothers and start to cry in pulses. Crying stops at reunion. The observed postnatal cry may be a human counterpart to the "separation distress call" which is a general phenomenon among several mammalian species, and serves to restore proximity to the mother. Our results suggest that in human newborns this cry is not dependent on earlier social experience and may be a genetically encoded reaction to separation. The findings are compatible with the opinion that the most appropriate position of the healthy full-term newborn baby after birth is in close body contact with the mother.