Abstract: An individual at risk for necrotizing enterocolitis and related disorders can be identified by measuring the level of at least one secretor antigen in a biological sample from the individual and comparing the measured level of the at least one secretor antigen to a predetermined value or a predetermined range of values. Among the secretor antigens which can be measured are: the H-1, H-2, Lewisb and Lewisy antigens and derivatives thereof (e.g., a sialylated form of Lewis a, Lewis x, Lewis b, Lewis y; H-1, H-2, Lewis a, Lewis x, Lewis b or Lewis y).