Mothers who were unable to breastfeed their babies found they often had a problem with their bottle-fed offspring. The babies were getting diarrhoea much more often than they should. This took the formula milk industry by surprise, because they had taken care to make sure their product contained the same substances as real breast milk. What could be missing? The answer was, of course, bacteria! Bacteria that live on milky nipples, and which are particularly common in the guts of breastfed babies:
