I would ask your Dr. for copies of his "studies" and then hand him a copy of the ones below.
J Obstet Gynecol Neonatal Nurs 2001 Mar-Apr;30(2):157-64
"Incubators versus mothers' arms: body temperature conservation in very-low-birth-weight premature infants." Mellien AC.
RESULTS: No significant variations were found in the infants' mean temperatures in the incubator, but the infants were significantly warmer while in their mothers' arms. CONCLUSION: VLBW premature infants can maintain a stable temperature in their mothers' arms without evidence of increased metabolic activity. Nurses can encourage mothers to hold their infants without fear of cold stress or weight loss.
Biol Res Nurs 2000 Jul;2(1):60-73 "Kangaroo care compared to incubators in maintaining body warmth in preterm infants."
Ludington-Hoe SM, Nguyen N, Swinth JY, Satyshur RD.
Many preterm infants cared for in incubators do not experience Kangaroo Care (KC), skin-to-skin contact with their mothers, due to fear of body heat loss when being held outside the incubator. Repeated measures ANOVA showed no change in abdominal temperature across all periods and between groups. Toe temperatures were significantly higher during KC than incubator periods, and maternal breast temperature met each infant's neutral thermal zone requirements within 5 min of onset of KC. Preterm infants similar to those studied here will maintain body warmth with up to 3 h of KC.
Acta Paediatr 1996 Nov;85(11):1354-60 "Fathers can effectively achieve heat conservation in healthy newborn infants." Christensson K.
The aim of the present study was to compare axillar and skin temperatures and metabolic adaptation in healthy, fullterm elective caesarean section delivered infants who were randomized to be cared-for either in (a) an incubator, (b) a cot, or (c) skin-to-skin with the father. Forty-four infants were studied. The mean axillary temperature increase was significantly greater in the skin-to-skin cared-for infants than in the cot cared-for group. There were no significant difference in mean temperature increase between skin-to-sin cared-for and incubator cared-for infants. Blood glucose increase was significant in the skin-to-skin group, but not in the other groups. Interestingly, at 24 h after birth the mean axillary temperature was significantly higher in the skin-to-skin group than in the incubator group. It can be concluded that fathers can effectively achieve heat conservation in healthy fullterm caesarean section delivered infants.
Acta Paediatr 1992 Jun-Jul;81(6-7):488-93 "Temperature, metabolic adaptation and crying in healthy full-term newborns cared for skin-to-skin or in a cot." Christensson K, Siles C, Moreno L, Belaustequi A, De La Fuente P, Lagercrantz H, Puyol P, Winberg J.
The aim of the present study was to compare temperatures, metabolic adaptation and crying behavior in 50 healthy, full-term, newborn infants who were randomized to be kept either skin-to-skin with the mother or next to the mother in a cot "separated". The babies were studied during the first 90 min after birth. Axillary and skin temperatures were significantly higher in the skin-to-skin group; at 90 min after birth blood glucose was also significantly higher and the return towards zero of the negative base-excess was more rapid as compared to the "separated" group. Babies kept in cots cried significantly more than those kept skin-to-skin with the mother. Keeping the baby skin-to-skin with the mother preserves energy and accelerates metabolic adaptation and may increase the well-being of the newborn.