Several studies of infant feeding show a causal relationship between time of introduction of formula containing cow protein and risk of onset of type-1 diabetes mellitus. This paper cites the literature pro and con and discusses lipocalins which might play a role in the pathogensis. beta Lactoglobulin, a major lipocalin protein in bovine milk, is homologous to the human protein glycodelin (PP14), a T cell modulator. Anti-beta lactoglobulin cross-reacts with glycodelin. The newborn intestine does not have complete "closure" and can pass food antigens. Beta lactoglobulin could generate antibody to glycodelin undermining T cell regulation of beta cells.