at a conference session once, a mother asked that very question, in reference to her child that had repeated ear infections, despite being completely breastfed. the answer that was given was, there are physical reasons that might contribute to the ear infections (short eustachian tube, some other anomaly, etc.), and that we would not know how much worse the health problems might be if the child were not breastfed. having spoken to a pediatric allergist who treats severely ill children with breastmilk, i get the distinct impression that it is very rare for him to see a child who is breastfed and has problems serious enough to warrant his attention. (i don't know numbers, in other words). of course bf is not enough to prevent every single case of everything, as there are other confounding factors. an article in the newest issue of the new yorker, about genetic testing of *every* resident of iceland, mentions that they have already seen some interesting preliminary results, including that the longest-lived citizens are related closely to each other, as are the sufferers of endometriosis. an interesting spin on the subject. carol brussel IBCLC who gets her medical news from lactnet and the new yorker (just kidding)