Are grandparents blood type can affect their grandchildrens type?

Grandparents' blood type cannot affect their grandchildren's blood type directly. Blood type is determined by the combination of alleles inherited from both parents and is not influenced by the blood type of the grandparents.

Each individual has two alleles for blood type, one inherited from each parent. Alleles can be either dominant or recessive. The A and B alleles for blood type are dominant, while the O allele is recessive. This means that if an individual has at least one A or B allele, they will have type A or type B blood, respectively. Only individuals with two O alleles will have type O blood.

Parents pass on one of their two alleles to their children. There are three possible allele combinations between a parent with type A blood and a parent with type B blood: A and B, A and O, and B and O. Depending on the combination, their children can have type A, type B, or type O blood. The same principle applies to other blood type combinations.

Grandparents do not contribute alleles directly to their grandchildren. Instead, they contribute their alleles to their children, who then pass them on to the grandchildren. Therefore, while the blood type of a grandparent may influence the blood type of their children, it does not directly determine the blood type of their grandchildren.