Anaemia (Hb < 11 g/dL) was significantly associated with age range from 12 to 23 months (aOR = 3.7 (1.7–7.9)), malaria parasite (aOR = 6.3 (1.5–53.5)), and birth-order higher than 3 (aOR = 1.6 (1.1–3.5)). The gene discussed is GSTM1; the disease is anemia (phenotype).