The Case for Maternity and Paternity DNA Testing

 This page was last updated on Wednesday, September 30, 2009

DNA testing has revealed that fifteen percent of those men named on a child's birth certificate are not the biological father of the child.  Thirty percent of the men accused of paternity and tested for paternity are not the biological father of the child.

In California, and in other States, it is possible for a woman to abort her husband's child and conceive a child by another man. The State presumes that the husband is the father and requires him to support the child.

Any woman can name any man as the father of her child and she or the government can sue him for support on behalf of the child. He then bears the burden of proof that he was not the father with the further monetary costs of testing and litigation.

Defects in Current California Law

Before me is a set of papers about California's Paternity Opportunity Program for unmarried parents.  Among other statements it states, "A declaration of paternity may be challenged in court only in the first two years after the child's birth by using blood and genetic tests that prove the man is not the biological father.  It also may overturned if the father or mother is able to prove that he/she signed the form because of fraud, duress, or material mistake of fact."  Later it states, "If either of you later change you mind after you sign this form, you must complete a Rescission Form for the Declaration of Paternity (CS 915) to cancel or rescind the declaration of paternity.  You must file the rescission form with the California Department of Child Support Services  within 60 days from the date you signed the declaration of paternity." 

The problem is that California law does not require that each person signing the form provide two passport type color photographs that are signed by themselves and by the person witnessing the transaction.   The law should require photo identification such as a driver's license or state identification card and the witness should record the identification numbers on the form.  The law should require the witness to sign under oath that the photographs are a true likeness of the persons signing the form.  Pasting these photographs onto the forms can provide an audit trail linking the signatures and photographs to the person making the declaration.

According to the instructions for the Rescission Form for the Declaration of Paternity, "Anyone who signed the Declaration for Paternity can use this form to cancel it within 60 days of signing the Declaration of Paternity, unless a court order for custody, visitation, or child support has also been entered.  This means either the man who signed or the child's mother can cancel the Declaration of Paternity.  Only one person's signature is necessary, by the other parent must be formally notified by certified mail, form the parent who is signing the rescission form ..." (bold type is on the form) (I added ellipses in place of "see the checklist below").  The instructions later specify that the person who signed the rescission form notify the other person using return receipt mail.  The problem is that the procedure for rescinding paternity does not require an audit trail as I proposed for Declaration of Paternity.   This existing procedure invites fraud.

Disputing Parentage

Until the late 1980's, the only way that a man could dispute paternity was with proof of impossible contact (usually ignored by many courts), lack of fertility (sterility, vasectomy - also ignored), and ABO blood typing.  Even when ABO blood typing excluded a man, some courts ignored the evidence and ascribed to paternity to him.  The California Supreme Court in 1946 ruled the Charlie Chaplin was the father of a child despite proof of blood group incompatibility.  Too many judges never cared for the facts.  One part of this essay will describe blood group testing and how it may be used to exclude parentage.  Keep in mind that this testing was designed to prevent physicians from transfusing patients with the wrong blood.  It was not designed to identify a particular individual.

Biological Parentage

A cell is a very small unit of protoplasm.  It usually has a nucleus surrounded by cytoplasm that is enclosed by a plasma membrane.  Chromosomes are gene bearing threadlike structures existing  in the cell nucleus.  Genes are units of inheritance usually occurring at specific points on a chromosome.  Except for sex cells, humans have 46 chromosomes in these nucleate cells.  Some cells do not have a nucleus.  One example is the erythrocyte or red blood cell.  This cell is actually a circular disk with concave faces.  This specialize cell contains hemoglobin that allows it to carry oxygen from the lungs to the tissues and carbon dioxide from the tissues to the lungs.  Humans have 23 chromosomes in their sex cells.  These sex cells are the ovum or egg of a female  and the sperm of a male.  A child inherits half of its chromosomes from the biological mother and the other half from the biological father making the total 46.

Blood Types

An allele is a pair of genes.  Each person has a pair of alleles relating to blood factors, one that determines blood type and the other determines rhesus factor.  One pair of genes determines blood type and the other pair of genes determines rhesus factor.  Each person has a pair of ABO blood genes that laboratories can test for the A antigen and the B antigen. When neither antigen is present, that person has type O blood.   When both antigens are present, that person has type AB blood.  A person has type A blood when only the A antigen is detected and these individuals can have the AO or the AA genotype.  Likewise, a person has type B blood when only the B antigen is detected and these individuals can have the BO or BB genotypes.  ABO blood testing cannot identify the genotypes that determine these blood types.

ABO blood also includes testing for serum antibodies.  This serves to confirm or dispute the antigen test.  If the test results do not agree, the laboratory must resolve the discrepancy.  Since reactions are strong, weaker than usual reactions indicate poor technique, faulty reagents, or incompetence.  Some laboratories have poor standards and no quality control.  It was not until 1990 that researchers determined that A and B were the co-dominant versions of the same gene and that O was its recessive version.  Persons who have the A antigen on the surface of their red cells will not produce anti-A antibodies because that antibody would cause the destruction of their own blood.  For that same reason, persons who have the B antigen will not produce anti-B antibodies.  That explains why persons who have the A and B antigens will not produce anti-A or anti-B antibodies.

Rhesus Factor

Each person has a pair Rhesus Factor blood genes that laboratories can test for the Rhesus antigen. When the test has not detected the antigen, that person's blood is typed Rh negative (Rh-). Otherwise, it is typed Rh positive (Rh+). The problem with blood testing is that it cannot distinguish between the (Rh+ / Rh-) and the (Rh+ / Rh+) genotypes.

When a woman who has Rh negative blood and has been exposed in the past to Rh positive blood from a previous pregnancy or by some other means, she may have developed antibodies to the Rh factor and this can harm the unborn child. Physicians have procedures that address this condition and that is why it is very important that women with Rh negative blood see a physician at the first sign of pregnancy.  These percentages vary slightly from source to source and are applicable to Western Europe and North America. Other regions may have a different distribution.

Here is a simple method of determining the possible ABO genotypes of a child.  Put the letters of the mother's genotype in the pink column headers in alphabetical order.  Then put the letters of the father's genotype in the blue row headers in alphabetical order.  Now, combine the letters in each row-column intersection in alphabetical order.

The same method applies to determining the possible rhesus genotypes of a child.  I substituted the letter 'M' for the 'minus' symbol and the letter 'P' for the 'plus' symbol.  Rh negative is always represented by 'MM' or '- -' but Rh positive can be represented by either 'MP' (- +) or 'PP' (++).  

I used the most common blood types in the following table to show how blood typing can exclude paternity or maternity.  The biological union of a person having type [AO+] blood with a person having type [OO+] blood can only have children with [OO-], [OO+], [AO-], and [AO+] blood types. 

The biological union of a persons with type [A-] and [O-] respectively can only produce children with [O-] and [A-] blood types; or so it seems.

Now see the results when blood type [A-] is not represented by [AO-] but by [AA-] in the following table.

The biological union of a person having type [AA -] blood with a person having type [OO-] blood can only yield children with type [AO-] blood.  But since blood testing cannot distinguish between type AO and type AA blood, the unfortunate male with type AA blood could be held as the father of a child with type O blood. 

The following matrix shows the possible blood genotypes of a child (in the blue columns and rows) resulting from the genotypes of its biological parents.  Use one row and one column for each parent's genotype shown in the grey titled boxes.  The child's possible genotypes is at the intersection of the selected row and column.

The following table shows how to determine the provisional father's blood type when the child's and the mother's blood type is known.  Use the columns (green) for the child blood type and the rows (pink) for the mother's blood type.  The intersection of the selected column and row gives the possible blood types of the provisional father.  For an example, if a woman has blood type B and her child has blood B, the blood types of the possible father can be found by looking in the block in row B under column B.   In this example, the provisional father can any male from the four possible blood groups.

Through the years, those who read my work have asked me about their having a different blood type and rhesus factor from their parents. So, I have added two tables to my paper so that others can satisfy their curiosity and understand why ABO blood testing is not a good test of paternity.

The following tables are designed to show symmetry. The light-blue column headers denote the blood type of the father. The light red row header denotes the blood type of the mother. At the intersection of the row and column is a light-green rectangle that gives all of the blood types of their biological child. The same is true for the rhesus factor table but chose, out of brevity to use the letters ‘P’ for positive and ‘N’ for negative.

DNA Testing

Blood typing cannot identify a child's parents but DNA testing can.  Nature stores our genetic information in molecules of deoxyribonucleic acid (DNA). Each person's DNA is determined at conception when a sperm cell fertilizes an egg cell producing a zygote.  Non-identical twins (triplets etc) occur when separate egg cells are fertilized by separate sperm cells producing multiple unique zygotes.  DNA testing can differentiate between these persons.  When a zygote divides to form two or more separate copies of itself it creates genetically identical twins, triplets, quads, etc. that have the same DNA. Therefore, DNA testing cannot differentiate between these persons.  However, each person has a unique set of figure prints and these figure prints can be used to identify a specific individual.

The DNA of a person is identical throughout a person's body. All human cells (except red blood cells) contain DNA. The DNA is determined at conception and does not change throughout the life of an individual.  All persons formed from a unique zygote have a unique DNA structure.

DNA testing can link a person to a crime or exonerate a person of a crime. It can establish maternity and paternity. DNA testing is much more of a test of exclusion than blood typing.  There are two methods that laboratories use to perform DNA testing.  Both methods have advantages and disadvantages.  Both methods can use painless saliva or swap samples taken from inside of the mouth.  RFLP (restriction fragment length polymorphism) breaks the DNA structure into smaller fragments at specific points that it then measures. The problem with RFLP is that it requires much more material and take more time than PCR.  PCR (polymerase chain reaction) takes a small amount of material and replicates a specific region of DNA to a point that it is measurable. PCR yields faster results and its advantage is that it can use much smaller amounts of material.  In prior revisions of this essay, I have preferred RFLP over PCR but now I prefer PCR over RFLP.  My reasons are stated in the last paragraph of this essay.

DNA testing did not become available until the late 1980's but now it is available to families at a reasonable cost.  According to the DNA Diagnostics Center, the cost of DNA testing was more than $1,000 in 1990.  Now DNA paternity tests with or without the mother are less than $500. I strongly recommend that DNA parental testing include both parents and the child.

Besides its ability to determine maternity and paternity, DNA testing has other uses. Though unusual, hospitals have switched babies and a few children are stolen from hospitals. This is why I  recommend that DNA collection is performed upon the birth of a child.  A child as the right to know its genetic history so that she or he can receive proper medical care for inherited conditions.  Moreover, no longer will "He is not your father"  be a disgruntled woman's weapon.  Moreover, DNA testing should be a standard procedure.  It is painless and affordable. I also recommend that health insurance carriers add this procedure to their standard coverage.

Hospital officials will want the husband to endorse the birth certificate at the time of birth.  Wait for the results of the DNA test.  Laboratories can return the results within hours.  The test may unexpectedly reveal that the husband is not the biological father but the wife is the biological mother of the child. The child and the biological father and his family may have rights regarding the infant.

Under these circumstances, the husband may consider among other arrangements:

• Welcome the child into his household and raise the child as his own.
• Place the child with its biological father (this is not often practical).
• Divorce for criminal intent, behavior, or fraud.

Child Support

Many do not realize that in certain jurisdictions the amount of child support is not solely determined by the purported parent's personal income.  If the non-custodial parent has a live-in partner or has remarried, and the new spouse or partner works, then the total household income can be considered in computing child support (some jurisdictions limit the amount).  The income earner pays the income taxes on the money that goes for child support and the recipient does not.  Most jurisdictions do not require the custodial parent to account for the expenditure of funds received as child support.  This non-accountability has led to numerous abuses (such as wage garnishment) that are beyond the scope of this paper.

About Prior Probability At 0.50

Polymerase chain reaction (PCR) testing requires less material and Restriction fragment length polymorphism (RFLP) requires more material.  I have read Forensic DNA Typing by John M. Bultler (IBSN-13: 978-0-12-147952-7) and I now prefer Polymerase Chain Reaction (PCR) testing.  The reliability of DNA testing is dependent upon the reference population sample it uses. For example, the genetic makeup for an Argentinean database might not be the same for The United States and accredited DNA testing services may have addressed this issue.

I obtained Interpreting DNA Evidence by Ian W. Evett and Bruce S. Weir (ISBN 0-87893-155-4). The authors wrote "We do not advocate the use of this probability of paternity because of the implicit assumption of a prior probability of 0.5, irrespective of the non genetic evidence . . . The assumption of 50% prior probability is difficult to defend."  Following this passage is a table called Probabilities of paternity for a range of paternity index and prior probability values. Starting at a prior probability value of 0.500, the next numbers in sequence were 0.500, 0.90909, 0.99009, and 0.9990010. What the author's conveyed was that any non zero prior probability value produces skewed results in favor of paternity.

If the table was called Probabilities of maternity for a range of maternity index and prior probability values, then nearly every woman could be proved to be the mother of any child that she did not bear. So, in both instances any non zero probability value produces absurd results.  I will write more on this subject in future updates to this paper.  I wish to add that the testing laboratory should be accredited by the American Association of Blood Banks (AABB) or some other competent authority.

The notion of prior probability is a fraud because when a proper DNA test is processed, the technician should not have any notion of whom or what is being tested. The standard of testing is that certain genetic markers are present or are not present. Years ago, many DNA testing clinics were operated by radical feminists who advocated prior priority at 50 percent. Those clinics do not now exist.

DNA Testing Methods

Restriction Fragment Length Polymorphism (RFLP) appeared in our lexicon in 1982 and Polymerase Chain Reaction appeared in our lexicon in 1987.  PCR testing was not immediately introduced because there were conflicting patent claims that had to be resolved by the United States Patent Office. According to my best sources, the PCR method was patented by Kary Mullis who invented the technology in 1983. The problem was that there was a dispute that resulted in at least one lawsuit that caused considerable delay. The United States Patent Office helped to resolve the problem and in 1993.  Mr. Kary Mullis was awarded the Nobel Prize in Chemistry for his work.

Edward S. Nunes

 

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