DNA Paternity Testing - How to Test in Absence of the Father

DNA paternity testing can prove paternity to within 99.99% accuracy, more than acceptable as legal proof of fatherhood. What happens, however, if the suspected father is not available to provide a sample, or refuses to do so?

There is no better method of proving that someone is the biological father of his child than DNA testing. The DNA of the father and child can be compared to within 99.99% certainty, more than enough for courts legally to pronounce the biological father of a child - or even to legally deny it.

Many men are reluctant to take part in such tests for their own reasons, and some may be deceased or even unable to be contacted for one reason or another.  In such cases there are ways of collecting samples and having the DNA test carried out.

Testing Blood Relatives to Prove Paternity

A child's paternity can be proved through a technique known as DNA Relationship testing, which involves testing relatives of the alleged father.  For this to be relevant there must be a proven relationship from the person tested to the father.

Grandparents, uncles, aunts, and even cousins, nieces and nephews of the child can be used as subjects. The match might not be perfect but there is only so far that such test can go, although for any but legal reasons, such matches are more or less conclusive.

What is conclusive is a DNA match for a male child using the Y chromosome.  The chromosomes of a human being can be one of two sex types, known as X and Y. Human DNA consists 46 chromosomes, two of which determine the sex. During reproduction, the human egg contains 23 chromosomes, half of what is needed to form an embryo. One of these 23 is the sex chromosome, and in the case of the female egg this is a Y chromosome.

The sperm contains either an X or a Y chromosome, and when the sperm and egg combine to form the full complement of 46, the two sex chromosomes are either X-X (female) or X-Y (male).

A relatively new DNA analytical procedure is able to test repeating sections of the Y chromosome to prove paternity down the male line. Known as the Y-Short Term Repeats test (Y-STR), this can be used on blood male relatives, such as the child's grandfather on the male side, brother, cousins, nephews or uncles, all on the male side.

Because the Y chromosome does not change down the generations, it can be used to prove paternity or otherwise, even though the actual father is not available for testing. This form of DNA paternity testing might be required by the courts, in which case it would be organized by your attorney, but you can also contact the company that will be doing the test, and ask their advice on what is necessary and who should provide the sample.

How DNA Paternity Tests can be Carried out in the Father's Absence

The most accurate way of proving biological fatherhood is by means of DNA paternity tests, involving the analysis and comparison of the DNA of father and child. What if the suspected father cannot be contacted or refuses the test?

Biological paternity can be proved to within 99.99% accuracy by DNA screening using samples from both the child and the father. This means that both subjects must be available for the samples to be taken. What happens when either subject is not available for the sample to be taken.

In normal circumstances, there is rarely any reason why the child should not be available, but prospective fathers might be living or working abroad, and not easy to contact, they might be unwilling to take the test or even be deceased.  In such cases there are ways in which the DNA paternity test can still be carried out.

How Relatives can be used to Establish Paternity

In the absence of a sample from the father, it is still possible for biological paternity to be established through DNA testing on relatives of the child.  Grandparents, aunts and uncles and siblings of the child can be used to determine the disputed paternity when a DNA sample from the suspected father is not available.

Known as relationship testing, these types of DNA matching are not always legally binding, but can be accurate enough for people wanting to know whether or not a specific person is liable to be the father or not.  In many cases, results are so accurate that  it would have to be an unlikely coincidence if they were not.

However, more is needed for legal purposes, such as legacies and inheritances. One test that has been used in DNA analysis of samples collected after sex offences, such as rape, is referred to as Y-STR, which refers to short term repeats of fragments of the Y DNA of male children, and it has to be stressed that this applies only to sons, and not daughters.

The Y chromosome occurs only in males.  When the 23 chromosome of the male and female sex gametes combine to create the 46 chromosomes of a human being, one chromosome from each gamete determine the sex of the individual. Male gametes (spermatozoa) contain either an X or a Y sex chromosome (about equal numbers of each) and the female gamete (ovule) only the X chromosome, so the X-Y combination is male. 

The Y chromosome does not appreciably change down the male genetic lineage, and so can be use to determined paternity. Any male member of the suspected father's blood-line can be tested for short-term repeating patterns in their Y chromosome to prove a direct relationship with both the child and his father.  Brothers, nephews, uncles or grandfathers will all share these same repeats.

In this way, the paternity of male children can be proved in the eyes of the law, and the presence of the father is not necessary - just one of his male relatives. If you feel that this type of test might be needed, you should contact the laboratory you will be using and explain the circumstances, and they will advise on the best course of action. 

If  Y-STR testing is needed they will inform you whether or not they can carry it out, and also of what other options are open to you. They will also arrange any legal stipulations, such as notarization of the sample collection and the security needed to transport it to the laboratory for the DNA paternity tests.

How to Carry out Absent Father DNA Paternity Testing

DNA paternity testing is the most widely used means of establishing the biological father of a child. What is the situation when the father is not available to provide the DNA sample necessary?

The reason for the popularity of DNA testing to prove paternity is that it is the most accurately known means of doing so, and the 99.99% certainty it offers is acceptable to courts as legal proof. For such a test to be carried out, it is essential that samples be taken from both the child and the prospective parent, and that such samples are notarized as belonging to the correct subject.

This is not normally a problem, but in the case that either of the subjects, generally the father, is unavailable to provide a sample, the test can still be carried in a manner acceptable to the courts.

Making Use of the Relatives

If the father is not available for testing, or refuses to take part, one of his relatives can be used instead, in what is known as Relationship Analysis. This is based upon the fact that the DNA of a child's grandparents, uncle and aunts and brothers and sisters is going to be very close to that of his or her father.

It is a technique that is frequently used by people who want to find out for themselves whether or not a specific person is or is not the father, particularly when that person refuses to be tested. Characteristics are passed down the generations, and these are determined by the structure of their DNA. 

However, for a more legally acceptable test, modern technology has made use of the sex chromosomes, particularly in the case of disputed paternity of a son.  Male DNA contains an X and a Y chromosome, and female DNA only the X chromosome.  The Y chromosome remains more or less unaltered down the male lineage, and the DNA of any male blood relative can therefore be used to determine paternity - or deny it.

This test was developed from the DNA screening of samples taken from rape victims, particularly when relatives of the suspected offender were available for testing, but not the offender himself. Referred to as Y-STR testing, it involves testing the Y chromosome for short-term repeat fragments that indisputably proves the relationship. The test has to be carried out on relatives down the bloodline of the alleged father, such as his father (the child's grandfather), brothers (child's uncles) and other male children. Even his uncles' male children (cousins) will provide relevant Y chromosome repeating fragments.

In this way samples from the father are not needed to prove paternity and refusal to provide a DNA sample is no longer a safe way to avoid the DNA test being carried out. If you require such DNA paternity testing,  you are advised to contact the company carrying out the testing and they will advise on the best type of test to meet your needs, and who should be involved.