If the child’s parents are both blood type A, the child’s blood type is either: First, it is also blood type A. Since the child’s parents are both blood type A and are pure congeners, the child’s blood type at this time is type A, due to the genetic laws of inheritance. Next, there is the presence of O blood type. If the child’s parents’ blood type A is not purely congenital, there will be the appearance of blood type O. This is the result of normal genetic crossover and is also a normal blood type. If the child’s parents have A blood type, the child can only have A blood type or O blood type, and there can be no B blood type. If the child of a parent has B blood type and the parent has A blood type, genetic testing should be done in a timely manner, etc.