NOD mice fostered by NOR parents have a decreased incidence of T1D. Incidence of T1D in NOD male (left) and female (right) mice nursed by NOD (filled circle) or NOR (filled square) mothers. Data combined from two separate groups of cross-fostered pups. Significance was determined by the Mantel-Cox Text. *P = 0.0013 at 32 weeks of age.