Blood groups can help to infer parent-child relationships, but they do not provide complete evidence.Blood type is determined by genes, such as the ABO or Rh type, inherited from both parents.For example, if both parents have type O, the child will always be type O. However, if the parents’ blood types are A and B, the child may be type A, B, AB or O.Therefore, while blood type may negate a parent-child relationship, it is not sufficient to prove it and DNA testing is required.
The table below shows possible combinations of parents’ blood types if the child’s blood type is A, B, AB or O.
| Child’s blood type | Father’s blood type. | Mother’s blood group |
|---|---|---|
| Type A | Type A, Type AB, Type O | Type A, Type AB, Type O |
| Type B | Type B, Type AB, Type O | Type B, Type AB, Type O |
| Type AB | Type A, Type B, Type AB | Type A, Type B, Type AB |
| Type O | Type O, Type A, Type B | Type O, Type A, Type B |
Details: .
- Type A children: one of the parents is type A or AB and the other type A, O or AB.
- Type B children: one of the parents is type B or AB and the other type B, O or AB.
- Children of type AB: one parent is type A or AB and the other type B or AB.
- Type O children: both parents type O or a combination of type A and B.
Supervisor of the article
Dr. Hiroshi Oka
Graduated from Keio University, Faculty of Medicine
Doctor of Medicine
Medical Doctor
