This chapter focuses on the functional properties of breastfeeding and its role on the relationship mother/newborn. Human milk components make it an inimitable mixture and the optimal nutrition for newborns. Far from being only a source of nutritional elements, human milk has got a lot of properties, most of them yet to be discovered. It has been proved that exclusive breastfeeding for 6 months in developing countries could prevent 13% of the global childhood mortality. This explains why World Health Organization and American Academy of Pediatrics are strongly requesting 6 months of exclusive breastfeeding in their guidelines. Breastfeeding provides a lot of physiological benefits for the child such as protection against infections, de...