San Diego Divorce Lawyer

Paternity Testing Basics – ABO Blood Testing

Paternity testing is a scientific process which can determine if a man is the biological father of a child. Such tests are frequently useful in child custody and child support cases where parentage is important. Whether a man wants to deny paternity or show that he is the biological parent of a child, there are two primary forms of testing used.

The ABO blood test is the simpler of the two main paternity testing methods. It revolves around the fact that a child’s blood type is determined in a fixed manner, and that there only four main blood types: A, B, AB, and O. These blood types are determined by the combination of two alleles, one from each parent. Each allele can be either A, B, or O. The A and B alleles are co-dominant, while the O allele is recessive. This means that a child with an A blood type would have either two A alleles or an A allele and an O allele, while an AB child could only possibly have one A allele and one B allele, and a O-type child could only have two O alleles.

Some combinations are impossible. Two O-type parents, for example, could not possibly give birth to a child with an AB blood type. Therefore, ABO blood testing could be used to rule out the possibility of paternity. That is, if a mother with O-type blood accuses another O-type man of being the father of her child, a test which revealed that the child had a AB blood type would contradict the accusation.

For more information on paternity tests, contact a San Diego divorce lawyer from Fischer & Van Thiel at 760-722-7646 today.