Among the normals (age range 5- 65 years), males had a mean Hb of 13.97 ± 1.51 g/dl while females had a mean Hb of 12.16 ± 1.74 g/dl while among β-thalassemia carriers (age range 3–58 years) males had a mean Hb of 11.96 ± 1.74 g/dl while females had a mean Hb of 10.86 ± 1.41 g/dl. Here, GSTM1 is linked to thalassemia.