Patient: Hello. I am a hemophiliac A male married to a normal female to have a child will the next generation be inherited. I asked several doctors at Fuzhou Union Hospital and they all gave me different answers. Some of them said that 50 percent of male children will be hereditary, while others said 100 percent of male children will not be hereditary. Will it be hereditary? The first affiliated hospital of Guangzhou University of Traditional Chinese Medicine has a hematology specialist, Chen Peng: The sex chromosome is XY in males and XX in females. The causative gene for hemophilia A is located on the X sex chromosome. Therefore, the genotype of male patients is X A-Y When a female produces an egg, the two X chromosomes of the female separate and are randomly assigned to the egg and passed to the next generation. Therefore, the sex chromosome that the next generation inherits from the mother can only be X. When a male patient produces sperm, the X A and Y chromosomes separate and are randomly assigned to the sperm and are passed to the next generation, and the sex chromosome that the next generation receives from the father may be X or Y. Therefore, when a male patient with hemophilia has a child, it is possible to pass the X chromosome, which carries the hemophilia gene, to the next generation, and it is also possible to pass the Y chromosome, which does not have the disease gene, to the next generation. The chances of passing it on to the next generation are 50%. Both have a 50% chance. When the next generation receives the X sex chromosome from the father, then, together with the X chromosome received from the mother, an XX combination is formed, which determines that this offspring must be a girl. This girl receives the disease-causing gene from the father, but since the X chromosome received by the girl from the mother does not have the disease-causing gene and can compensate for the defect in the father’s X chromosome, this girl will not develop the disease, but carries the disease-causing gene. When she gives birth to the next generation, the disease-causing gene may be passed on to the next generation in a big way. If the next generation inherits the Y chromosome from the father, the father’s Y chromosome is normal, and the X chromosome from the mother creates an XY combination, then the offspring must be a boy, and since the mother’s X chromosome is also normal, the boy is free of the disease-causing gene and will not develop the disease. Therefore, if a male hemophiliac has the next generation, if it is a girl, she must be a carrier but does not develop the disease, and if it is a boy, he must be normal.