??? In the clinic, many young fathers and mothers-to-be would take the results of the maternal screening test for thalassemia and ask me with some concern: “Doctor, I had the maternal screening test for thalassemia and the hemoglobin electrophoresis indicates that I am likely to have the thalassemia gene carrier, and I am planning to have a baby. After receiving the test results and reading them carefully, it can be found that the hemoglobin is still normal, but the mean cell volume (MCV) and mean hemoglobin volume (MCH) are often significantly lower in the hemoglobin carriers, who can grow up to marriageable age. The general rule for HbA and HbA2 on the hemoglobin electrophoresis test is: if both HbA and HbA2 are low, it is likely to be α-thalassemia; if HbA is low and HbA2 is high, it is likely to be β-thalassemia (remember, it is just a general rule). If the blood count and hemoglobin electrophoresis suggest the above, then a genetic test for thalassemia is essential, as it is the gold standard for confirming the diagnosis of thalassemia and the type of thalassemia. Then the question arises, if the genetic test for thalassemia comes back and one or both parents are carriers of the thalassemia gene, will the next generation develop thalassemia? There are several situations: 1. One parent is a carrier of alpha or beta thalassemia gene and the other parent is completely normal: the next generation has a 50% probability of carrying the same thalassemia gene as one parent and a 50% probability of being completely normal; 2. One parent is a carrier of alpha thalassemia gene and the other parent is a carrier of beta thalassemia gene: the next generation may be a carrier of alpha thalassemia gene and may be a carrier of beta thalassemia gene In this case, the next generation will not be heavy-duty poor because the α and β genes do not overlap; 3. Both parents are carriers of the same gene (both are carriers of α gene or both are carriers of β gene): the next generation has a 50% probability of being carriers of the gene, a 25% probability of being completely normal, and a 25% probability of being normal. The probability of the next generation being a carrier of the gene is 50%, the probability of the next generation being completely normal is 25%, and the probability of the next generation being a child with severe thalassemia is 25%. In order to implement eugenics and to avoid the birth of the 25% of children with severe thalassemia (which is still a high probability), it is necessary to do prenatal diagnosis and perform amniocentesis to detect the type of thalassemia gene in the fetus to ensure the birth of a healthy baby.