RESUMEN
In the present paper, the methodology and some new finds related to the maternal effect observed in the hemoglobinopathies are discussed. The most important aspect to emphasise when discussing this effect is the absence of biases from the methodology employed, since the Mendelian proportion is investigated in the filial generation with independent observations. Therefore, no statistical correction is needed. Recently, the Mendelian proportion was also tested in the progeny of 76 hemoglobin C trait (AC) probands married to individuals with normal hemoglobin (AA). On excess of births of heterozigotes in the offspring of the 40 AC mothers (66 AC: 30 AA; c2 = 13.5, p < 0.05) married to homozygous normal fathers was observed, but not for births to the reverse parental combination (36 AC: 34 AA; c2 = 0.057; 0.8 < p < 0.9). This fascinating phenomenon, also observed in the hemoglobin S and in the beta-thalassemia, need to be elucidated by evolutionary biologists.