| Well, for certain we all are
exactly the product of our parents. The proof of this is in our Blood. Let's take a look
at some of the "rules" of Blood type genetics for the population of the United
States. (Other population groups have differing Blood type statistics. See information HERE.) There are basically four primary common Blood
types. The most common by far is Blood type O, followed by type A, type B, and the least
common is Blood type AB. Blood type is determined by the "alleles" that we
inherit from our parents. Alleles are different possible types of a particular gene, in
this case the gene(s) controlling our Blood type. There are three common Blood type
alleles: A, B, and O. We all have two alleles, one inherited from each parent. The
possible combinations of the three alleles are: OO; AO; BO; AB; AA; BB. Blood types A and B are called "codominant"
alleles, (they share in the controlling influence of our genetic Blood make-up) while O is
"recessive." A codominant allele is apparent, or dominant, even if only one is
present; a recessive allele is apparent only if two recessive alleles are present. Since
Blood type O is recessive, it is not apparent if the person inherits an A or B allele
along with it.
Therefore, there are certain
possible allele combinations in a particular Blood type:
OO = Blood type O
AO = Blood type A
BO = Blood type B
AB = Blood type AB
AA = Blood type A
BB = Blood type B
What all of this means to the
paternity puzzle is that ABO Blood typing can only give some preliminary indications as to
possible paternity. This rule, however, can not be universally applied, because the vast
majority of most people in Caucasian populations has only two of those types (A and O).
This means that a male may have a type consistent with paternity and still not be the
father of the tested child. DNA typing always yields a more reliable conclusion regarding
paternity and is the final word in paternity legal cases.
There are some good reasons for
a husband to not donate Blood to his wife during her childbearing years.
During this time, a women who plans to become pregnant, receiving Blood from her husband
may pose a small risk to the infants born of these pregnancies. If, after the Blood
transfusion the woman develops an antibody to an antigen on the father's red Blood cells,
and the subsequently born fetus inherits the father's red cell antigen, the antibody from
the mother may enter the Bloodstream of the fetus causing destruction of fetal red Blood
cells. This may cause serious anemia in the fetus and excessive jaundice in the infant
after birth. This is a known major cause of brain damage. Special Blood transfusions,
using selected red Blood cells that do not have the particular in-compatible and offending
antigen, are available when this condition is pre-diagnosed. Of course, we suggest
autologous Blood donation for the mother. However, for those mothers who are unable to
make an autologous donation, the decision to select her husband as a donor should always
take this risk under consideration, and specific consultation with your pediatrician on
this subject is essential.
There are instances when the following chart
will not be accurate. In the case of a mutation, the Blood typings may not hold true in
the question of parentage.
The chart should be used as general
information only. All health care decisions should only be made with consultation from
your physician. Ask before you act.
| PARENTS'
BLOOD TYPES |
POSSIBLE
CHILD |
NOT
POSSIBLE CHILD |
|
A and A |
A, O |
B, AB |
|
A and B |
A, B, AB, O |
no |
|
A and AB |
A, B, AB |
O |
|
A and O |
A, O |
B, AB |
|
B and B |
B, O |
A, AB |
|
B and AB |
A, B, AB |
O |
|
B and O |
B, O |
A, AB |
|
AB and AB |
A, B, AB |
O |
|
AB and O |
A, B |
AB, O |
|
O and O |
O |
A, B, AB |
Rh status works in a way
similar to Blood type groups. If you are Rh positive, you may have genes for both positive
and negative. If you are Rh negative, you have two genes for Rh negative. In the following
chart, the child's Rh factor is in the white area.
Father's Group |
Mother's Group |
Rh + |
Rh - |
Rh + |
Rh +,
Rh - |
Rh +,
Rh - |
Rh - |
Rh +,
Rh - |
Rh - |
|
Blood Types and Compatibility Chart
World Distribution of ABO Blood Types |
