How to determine the blood type of a child by the blood group of the parents?

The birth of a child is always a long-awaited and mysterious process. Even before he is born, the future mother already wants to know whom he will look like, what color his eyes, hair. Also, quite often the mother is interested in the question as to which blood type the child will have and how to determine it by the blood group of his parents.

What is the blood group and how is it determined?

The blood group of a person is determined by the presence or absence of special compounds - antigens. They are usually denoted by the letters of the Latin alphabet (A and B). Depending on the absence or presence of them, 4 blood groups were isolated. In fact, not so long ago, scientists have established that there are many more. However, so far, the so-called system AB0, is used for blood transfusion. According to her, blood groups are defined as follows:

How is the heredity of the blood group established?

To determine the blood type of the child, the methods of genetics are used according to the blood group of the parents, so it is not difficult to learn it. To do this, it is sufficient to apply the laws of Mendel, which are passed in school at the lessons of biology, in practice. According to them the inheritance of blood groups is carried out as follows.

So if the parents have 1 group, then it will be the same for both children and children. no parent has no antigens in the blood - I (0).

If one spouse has 1, and the other has 2, then children can inherit the second group, too. one of the parents in the blood does not have antigens, and from the second he will get the antigen A, which is responsible for the 2 blood group.

A similar situation occurs if one parent has 1 and the other has a 3 group. However, in this case, the child can be born with both the first and the third group.

In those cases when one parent has 3, and the second has 2 blood groups, a child with equal probability (25%) can have any group.

4, the blood group is rare. in order for a child to have such blood, it is necessary to have simultaneously 2 antigens.

How is the Rh factor inherited?

The term "rhesus factor" means a protein that is present in the blood of 85% of all people. Those people in whose blood it is present are Rh-positive. In the opposite case, they speak of Rh-negative blood.

In order to determine such a parameter as the Rh factor of a child in the blood group of his parents, they also resort to the laws of genetics. For this, a pair of genes, which are usually denoted by DD, Dd, dd, are sufficient for research. Large letters mean that the gene is dominant, i.e. so designate those people who have a Rh protein in their blood.

So, if parents have a heterozygous Rhesus (Dd), then in 75% of cases their children will also have a positive Rh, and only 25% - negative.

Heterozygosity appears in the child as a result, so to speak, of the conflictual Rh-negative factor of the mother, and can be transmitted to many generations. However, in most cases, this does not happen, because in this situation, the probability of pregnancy is very small, and if it does, it ends with an early abortion.

Thus, as can be seen from the article, it is not difficult to determine the blood type of a child by parents, especially since there is a table in which the probability of transmission of a particular group is indicated, depending on the blood of the parents. Looking into it, the expectant mother will be able to independently know what kind of blood will be her baby. For this, it is enough to know only your blood group and the baby's dad.