A Norwegian professor said Thursday feeding a baby breast milk does not make them healthier than those fed formula.

Professor Sven Carlsen found that while breast-fed infants are slightly healthier than bottle fed babies, it is not the milk that is responsible.

Carslen claims a baby's overall health is determined prior to birth and dependent on hormone levels in the mother's womb.

"The answer is simple. If a mother is able to breast-feed, and does so, this ability is essentially proof that the baby has already had an optimal life inside the womb," the professor said.

When a woman has high levels of male hormones in the womb the flow of nutrients to the baby is affected, the report went on. The hormones also affect her ability to breast-feed, making her offspring more likely to be bottle fed.

"Pregnant women who have higher levels of androgens breast-feed less ... probably, this is a direct effect of hormones that simply limit nursing ability, by reducing milk production in the breast," Carlsen added.

The study conducted by the Norwegian University of Science and Technology, Trondheim reviewed data from more than 50 international studies looking at the relationship between breast-feeding and health.

Carlsen said the study found no evidence that breast-feeding reduced the risk of asthma and allergies in children. He added the only benefit supported by genuine evidence is a "small IQ advantage."

However the U.K. government dismissed the claim. A spokesman for the department of Health told NewsCore.

"The Government recognizes that breast-feeding is the best form of nutrition for infants. It gives health benefits for both the baby and the mother - even after they are no longer breastfeeding.

"Our advice is based on World Health Organization guidance which recommends exclusive breast-feeding through its report Optimal Duration of Exclusive Breast-Feeding and this is backed up by the Scientific Advisory Committee on Nutrition in this country.

U.S. government health officials also recommend breast-feeding over formula feeding.