"More evidence is being put forward that breastfed babies eventually become more intelligent than those who are fed with formula milk.

Canada's McGill University found breastfed babies ended up performing better in IQ tests by the age of six.

But the researchers were unsure whether it was related to the breast milk itself or the bond from breastfeeding."

http://news.bbc.co.uk/2/hi/health/7385097.stm