Paternity test – clarity lies in the genes
Paternity tests have been used for over 100 years to establish paternity between the potential father and the children. While in the past primarily external characteristics were used to substantiate paternity, later blood group tests were among the most common methods. Today, DNA paternity tests are the most scientific method to either 100% exclude or 99.9999999% confirm paternity. Whereas in the case of maternity doubts arise only in exceptional cases (for example, if the baby has been swapped after birth), the situation is fundamentally different in the case of paternity. External characteristics can provide the first clues to an existing paternity. If the blood groups of the test persons are known, this information can also provide information on whether the potential father is also the biological father.
Historical development of DNA paternity test
In traditional societies, people resorted to external characteristics to determine the paternity of a newborn. With advances in medicine and technology, more and more reliable methods became established to scientifically confirm paternity between the potential father and the child. In 1900, the Austrian biologist and physician Karl Landsteiner discovered blood groups. This made it possible for the first time to substantiate the probability of potential fathers or to exclude certain persons as fathers. In 1930, paternity tests based on blood grouping were also admitted to courts.
In 1930, serological tests were performed for the first time in combination with rhesus factors according to Kell and Duffy. Although this made more informative tests such as pure blood group analysis possible, the results of serological tests were also not yet conclusive enough.
paternity testing was achieved in 1970 through HLA typing. HLA is the human leukocyte antigen. HLA is a protein that is present in all human body cells, but is more abundant in white blood cells. Paternity tests of HLA typing were based on this. The composition of this protein in the father was investigated. This made it possible to confirm paternity with a probability of 80%.
Scientists made further progress in this field in the 1980s. Paternity tests were performed here based on restriction fragment length polymorphism. For the first time, it was possible to examine the genetic material itself. With the help of this method, it was possible to cut out base sequences from the DNA. These were then identified and examined for matches. Analyses based on these tests were able to predict a probability of 99.9%. However, it proved disadvantageous that a lot of genetic material was needed to perform these tests.
Today, the PCR (polymerase chain reaction) method is the primary method used. Only very small amounts of DNA material are needed to obtain a reliable result. This makes it possible to test even small children and babies already. The STR (Short Tandem Repeat) method even requires only cell fragments or very small cells to screen the involved subjects for matches. Here, genetic material found on a baby’s pacifier is already sufficient for the test to be successful.
Requirements for carrying out a paternity test
To perform a paternity test, the DNA material of the child as well as the potential father is needed. Informed consent from all persons involved must also be provided. If the potential father does not agree to the paternity test being carried out, or if the mother refuses to give her consent, these consent forms must be enforced by the courts. If the child has already reached the age of 18, the declaration of consent of the child to be tested must also be available. Furthermore, a paternity test can only be performed if the collection of the saliva sample has been confirmed by a witness.
What is meant by a paternity test?
Each person has a unique DNA, which contains the genetic material. This DNA is in turn composed of the DNA from both parents, half of which is passed on to the child. Paternity tests are based on this. By taking DNA samples from both parties, they are then analyzed for matches.
However, there is still a fundamental difference between a paternity test and a paternity opinion. A paternity test can be performed for private purposes, but it has no probative value in court. However, a paternity test can also provide initial clarity about an existing paternity and is often the starting point for a court-ordered paternity opinion.
Scientific basis of a paternity test
Almost every human cell is equipped with a nucleus. This cell nucleus contains the genetic information, which in turn is located as a gene on the chromosomes. Of these chromosomes, healthy people have 46. Half of the chromosomes are inherited from the mother, the other half from the father. These chromosomes also contain the sex chromosomes X and Y. While men carry the combination XY, women have the combination XX. The chromosomes themselves consist of DNA, the deoxyribonucleic acid. This occurs as a macromolecule in almost every cell of a living being. The information located there regulates the function and development of the human being.
DNA consists of nucleotides, which in turn consist of sugar, phosphate residue and one of four different bases. These bases are named adenine, thymine, guanine and cytosine. Simplified, these are also referred to as A, T, G and C. Three of these bases are combined to form an amino acid.
There are variations in each chromosome, which makes the DNA of individuals different. However, there are extensive similarities in DNA between children and parents. These matches between parental and child DNA make it possible to exclude or confirm paternity.
In a parentage report, the chromosomes are compared with each other. Paternity is excluded, for example, if there are certain features in the DNA strands that are not components in the parental DNA. In order to avoid sources of error, the investigation is not based on just one characteristic, but rather numerous matches are examined.
How is a paternity test performed?
If the consent of all parties involved is available, a paternity test can be performed today without complications. Numerous Internet providers offer such test sets, which contain everything needed to perform such a test. The most common is tissue sampling in the form of saliva samples. In the form of a mucosal swab on the inside of the cheek, DNA sections can be sent in. Other samples can be blood samples or hair roots in rare cases. It is also necessary that a neutral person is present to document this execution and act as a witness. This may be a notary, the public health officer or family physician, or even a laboratory employee. Then it is the turn of the laboratory, which analyzes the DNA samples taken.
In the laboratory, the collected samples must first be processed for further analysis in order to provide results. To do this, chemicals are added to the samples and the genetic material is separated from the proteins and other components found in the cells. In the end, a pure DNA sample is available, which can now be processed further.
Subsequently, the features in the DNA must be amplified. Paternity tests have the condition that only few tissue samples are needed. On the other hand, these also contain little DNA. This amount of DNA is too little for a reliable DNA analysis. A polymerase chain reaction is subsequently used to amplify the parts of interest for analysis. Only the Short Tandem Repeats (STR) are interesting here. These are short sections that do not contain hereditary information but provide information about matches. Since they differ fundamentally from person to person, it is primarily these components that are important for a DNA paternity test.
What methods are available?
Before there was the possibility of paternity by DNA analysis, blood groups were evaluated to determine paternity. Another possibility is a serological report or anthropological-hereditary report. Finally, the determination of paternity on the basis of DNA analysis is the most modern variant.
When determining paternity with the help of blood grouping, certain fathers are automatically excluded due to the inheritance rules. Serological reports are based on HLA antigens and other proteins present in the blood. In anthropological-hereditary reports, external characteristics were taken as a basis to conclude possible paternity.
In addition to these procedures, there is the possibility of performing a prenatal paternity test. This is only permitted in Germany if there is a legitimate interest and can then be ordered by the authorities. Such a case occurs when the mother has been abused and there is disagreement about who is eligible to be the father of her unborn child. If the pregnancy occurred as a result of a sexual offense, she will gain certainty through the prenatal paternity test and can decide for herself whether or not to give birth to her child.
Duration, costs and legal background
The cost of performing a paternity test ranges from 150 to 2000 euros. These costs depend on whether this test was carried out on the patient’s own premises, whether a laboratory was visited and whether the DNA paternity test is still linked to legal proceedings. The most favorable variant is the paternity test, which can be performed in the one premises. Here costs between 150 and 250 euros are due. If a private laboratory is commissioned, the costs amount to 200 to 700 euros. It is true that there are also cheaper offers on the Internet that attract customers with much lower prices. However, caution is advised with such offers, as foreign institutes are not bound by the German legal system and there are also significant differences in quality standards compared to German laboratories.
If legal proceedings are conducted to establish paternity, costs of 1000 euros are due. In addition, there are court and attorney fees, so that ultimately 2000 euros can arise.
The paternity itself is done within a few minutes. Stakeholders must allow for a waiting period of approx. 7 days before the result is available. Here, individual circumstances come into play, such as how busy the laboratory is and how informative the samples taken are. If the consent of persons involved is missing and the paternity test must first be ordered by the court, longer waiting times must be planned.
Since 2010, the Genetic Diagnostics Act (GenDG) has regulated that paternity tests carried out secretly are inadmissible. A test performed without mutual consent may result in penalties of up to 5000 euros. The laboratory also faces severe penalties if a test is performed without the consent of the parties involved. The basis for this change in the law is to be found in data protection. The collection of saliva samples and their examination in a laboratory represents a sensitive interference with the personal rights of the persons involved. If consent is refused by a member, it may be enforced by legal proceedings. This ensures that the personal rights of the persons involved are protected.
Data protection and test results – security at a high level
According to the Genetic Diagnostics Act, the medical staff involved in the paternity test must destroy the samples immediately if they are no longer needed for further examination. Data protection is subject to the strictest regulations. In addition, the persons involved can determine whether the data should be deleted or retained immediately after the parentage report is sent. A retention period of 30 years applies to the test results. If this is not desired, these results can also be destroyed beforehand.
The results of a paternity test provide a high degree of certainty. Paternity can be 100% ruled out or 99.99999% proven by DNA analysis. This applies only to DNA analysis. If paternity is determined by means of a blood grouping, statements can only be made here about which persons are possible fathers and which are not. However, blood grouping cannot confirm paternity.
A paternity test serves to clarify paternity. In this function, the test does not provide any information about hereditary diseases or genetic changes and genetic defects. Special other tests are required for this purpose.
When can the paternity test not be used?
Identical twins have the same DNA. In this case, the paternity test cannot tell which of the two brothers is the child’s biological father. In both cases, there would be a 99.99999% probability. However, since before the law there is only one father, the mother would be left in the dark about which man is now the actual father.
Conclusion:
Every year, 30,000 paternity tests are ordered. A paternity test provides clarity for all parties involved as to who the child’s biological father is. Preferably, such tests are used when the skin color after birth is fundamentally different from the skin color of the parents or when no similarity can be observed at a later age. The suspicion is strengthened when there is a resemblance not to the presumed father, but to a family friend or another member in the family. A paternity test also makes sense for dark-skinned children compared to their white parents. So it is quite true that dark skin color can skip a generation. Paternity in such a case is therefore not 100% excluded from the outset. Often paternity tests are also an effective way to restore peace in the family. Before considering a paternity test, however, one should be aware that serious consequences may result.