GSTM1 and methemoglobinemia: ; immature NADH-methemoglobin reductase systems with reduced capacity to cope with oxidative stress (levels at birth are only 50–60 % of adult levels) [18, 25, 26]; the presence of fetal hemoglobin which is more readily oxidized to MHb than adult Hb [18]; and a higher consumption of water per unit body weight, which renders them susceptible to methemoglobinemia if exposed to nitrates through drinking water [27].