The capacity of maternal IgGs to cross the placenta during pregnancy or the epithelial barrier during breastfeeding in an active FcRn-dependent manner can be exploited to educate the immune system of the offspring and confer protection in several human pathologies such as asthma, type-1 diabetes (T1D), hemophilia A (Figures 2B,C). This evidence concerns the gene FCGRT and type 1 diabetes mellitus.