Men over the age of 15 (Hb under 130 g/L), women over the age of 15 who are not pregnant (Hb under 120 g/L), and children between the ages of 12 and 14 (Hb under 120 g/L) are considered anemic. Pregnancy requires modifications to anemia definitions because of changes in homeostasis. This evidence concerns the gene GSTM1 and anemia.