The mother has O blood type and what blood type the son has is related to the specific blood type of the father. It may be in the form of A, B, or O blood type. Mothers are O blood type, the children’s blood type can be divided into the following types depending on the father’s blood type; sons and daughters are not different in terms of blood type. 1. The father is of blood type O: it is possible for a son to be of blood type O. 2. Father’s blood type A: it is possible for a son to have blood type A and O. 3. father’s blood type B: son’s blood type B and O are possible. 4. father’s blood type AB: son’s blood type B, A is possible. Blood type is ultimately determined by the combination of the three genetic factors A, B and O. Type O is recessive, and types A and B are dominant. In most cases, the possible blood type of a child can be initially deduced from the blood type of the parents. Blood type tests are often required during blood transfusions and pregnancy tests. Human blood types are categorized according to certain markers on the surface of red blood cells, and blood type tests can initially determine the blood relationship between two people. However, nowadays, if you want to determine the safest way to have a biological child, you should still check the genes through genetics, and relying on the blood type test alone is unreliable.