Breastfed babies are better behaved, says research
10 May 2011 Last updated at 10:31 BST
Children who are breastfed for four months or more develop fewer behaviour problems, Oxford researchers say.
The study, involving 10,000 mothers and their babies and in journal Archives of Disease in Childhood, says that may be because of the make-up of breast milk.
Professor Yvonne Kelly helped produce the research and told BBC Breakfast that "children who come from homes where they are breastfed are more likely to live in socially advantaged circumstances", but women should not feel guilty if they were unable to breastfeed.