In general, it is difficult to determine whether a child is biological or not entirely by blood type, and a paternity test is required to finalize the determination. There are four common blood types: A, B, AB and O. Some children may have the same blood type as one parent or different blood types from both parents, e.g., if the parents are of blood types A and B, the child’s blood type can be either A, B or AB. At present, the commonly used method to determine paternity is paternity testing, which is done by drawing blood to test the child’s DNA as well as the parent’s DNA, and the accuracy of the determination from the DNA point of view is relatively high.