Blood type can determine paternity, but the accuracy is not as high as that of DNA identification. Blood type is a genetic trait expressed in the form of blood antigens, and the blood typing system that is currently used more often in clinical practice is the ABO typing system. Blood type is genetically determined, but the blood type of the offspring is not necessarily the same as that of the parents. The gene that determines blood type is only one of many genetic loci, and paternity cannot be determined by blood type alone. For example, in the rare case of Bombay blood type, the normal ABO blood test does not detect the Bombay blood type and may mistake it for O blood type. Therefore, if people with Bombay blood type are tested for paternity, the results are often inaccurate. If you need to determine paternity, it is recommended to choose DNA paternity test which has the highest accuracy rate.