A gene found in 90% of the human race helps explain why breast-fed babies are more intelligent than infants raised on bottled milk, scientists have discovered. Researchers found that the IQs of children who had been breast fed were 6 to 7 points higher than bottle-fed babies—but only if they had a variant of the FADS2 gene, according to the study in the Proceedings of the National Academy of Sciences.
The gene helps turn fatty acids into brain nutrients, though scientists don't understand how breast feeding affects the process. The study demonstrates that "nature and nurture work together," said the lead researcher. Breast feeding has also been found to reduce infections and respiratory illnesses.