2001). Breastfeeding has been reported to be associated with a lower incidence of parasitic disease (Bilenko et al. 2008), and we speculate that one potential mechanism to explain this is the stimulation of endogenous IgE levels that may be advantageous to infant survival, particularly from an evolutionary perspective (i.e., those individuals with higher IgE levels may be more likely to thrive and survive until adulthood, increasing the chances of having offspring). This evidence concerns the gene IGHE and parasitic infectious disease.