Description

• All humans have one of four blood types: A, B, AB or O. Proteins known as ABO antigens determine blood type.
  
  

Genes

• ABO antigens are inherited from both parents. If the blood type of each parent is known, it is possible to predict which blood types a child may have.
  
  

Paternity Tests

• A potential father can be excluded from paternity if a blood-type test determines that the child has an ABO antigen not present in either the mother or the putative father.
  
  

Limitations

• Blood Typing can only exclude a possible father, not prove paternity. A blood-type test will exclude only 30 percent of the population from possible paternity. Also, in rare cases, mutations in DNA can produce children with unexpected blood types.
  
  

Considerations

• DNA paternity testing is preferred over blood typing because it is more than 99 percent accurate in proving paternity.