Includes a series of procedures aimed at clarifying the presence of a relationship between a man and a child. There are several main methods of establishing paternity: by external similarity (eye color, facial features), blood type, date of conception, as well as by the results of DNA analysis. The latter method is the most reliable and can be provided as evidence in court. Establishment of paternity is usually carried out by a geneticist.
Paternity Establishment Methods
Methods for establishing paternity differ in the degree of complexity, reliability of the results and the value of the data obtained in terms of the possibility of their use as evidence in court. Below are the most well-known methods for determining paternity:Determination of paternity by external signs
External signs such as eye color, hair and skin color, facial similarity, etc. cannot serve as a reason for confirming or refuting paternity. This is due to the fact that, although external signs are determined genetically, nevertheless, they can vary and appear to varying degrees from case to case. The inconsistency of the method of determining paternity on the basis of the external similarity of a child and a man is also confirmed by the fact of the existence of so-called doubles - people who do not have any kindred connection, but at the same time are very similar to each other in external data. Thus, it is impossible to determine the relationship between a man and a child on the basis of whether or not a child resembles his alleged father.Establishing paternity by date of conception and gestational age
The need to establish paternity often arises in cases when a woman has had sexual intercourse with different men during 1 menstrual cycle. In such situations, for a preliminary and inaccurate determination of paternity, you can try to calculate the date on which the maximum probability of conception fell. A man who has had sexual intercourse with a woman shortly before or after this date is most likely the father of the child. It was determined that in women with a regular menstrual cycle, the maximum probability of conception occurs in the middle of the menstrual cycle, that is, approximately 14-15 days after the start of the next menstrual period. However, as practical observations show, for many women, the moment of maximum probability of conception cannot be accurately determined. A detailed description of how to determine the likelihood of pregnancy at different periods of the menstrual cycle is presented in articles and. Determination of paternity based on comparing the possible date of conception with the date of sexual intercourse is greatly complicated by the fact that spermatozoa (male sex cells) can "survive" in a woman's body for 3-5 days after intercourse. This means that conception can occur several days after sex, and that the father of the child can be a man who had sexual intercourse with a woman several days before the possible date of conception, even if the woman had sex with another man directly on the date of conception. Determination of paternity is also possible on the basis of the term (age of pregnancy). The gestational age can also be set on an ultrasound scan, however, even with the most advanced ultrasound equipment, it is extremely difficult to establish the date of conception with an accuracy of the day. Cm. . Thus, determining paternity based on the possible date of conception or gestational age is completely impossible in cases where a woman has had sexual intercourse with different partners within a short period of time.Determination of paternity by blood group
Establishing paternity by blood type is a preliminary method for assessing the likelihood of consanguinity between a man and a child. With this method, a negative result is 99% accurate, while a positive result can be quite inaccurate. Due to the fact that the determination of the blood group of the child is carried out mainly after his birth, the method of determining paternity based on the study of the blood groups of the parents and the child is used only after the child is born. The principle of determining paternity by blood group and Rh factor (Rh factor) is that a child's blood group is determined by a set of genes that are passed on to him from his father and mother. Below is a table by which you can determine which blood type a child may have, depending on the blood type of his parents. How to use the table: the mother's blood type is shown vertically, the father's blood type is shown horizontally. In the cell of the table, located at the intersection of the blood groups of the mother and the father, the blood groups that the child may have are indicated.|
Father's blood type |
||||
| Mother's blood type | ||||
| I (0) | ||||
| II (A) | ||||
| III (B) | ||||
| IV (AB) | ||||
|
Father's blood type |
||
| Mother's blood type | ||
| Rh + | ||
| Rh- | ||
Determination of paternity based on DNA analysis
The DNA test for determining paternity is currently the most accurate and valuable method, as its results are very accurate and can be presented as evidence in court. The principle of establishing paternity based on a DNA test is as follows: In the DNA of each person there are special sequences of chemicals that are almost unique (that is, individual for each person). During conception, the child receives genetic material (unique sequences) from both parents. DNA analysis allows you to determine if there are unique DNA sequences of a possible father in the DNA of a child. The most accurate DNA test results can be obtained if biological material (for example, a blood sample or cell scraping) of the child, the alleged father and mother is provided to the laboratory for analysis. Nevertheless, if it is not possible to obtain material from the mother, the results will still be sufficiently substantiated and reliable. The accuracy of the DNA test is 100% when a negative result is obtained and 99.9% when a positive result is obtained. For DNA analysis, a negligible amount of biological material is required: as a rule, it is blood from a vein, scraping from the mucous membrane of the inner side of the cheek, hair, or nails. Since these materials can only be obtained from a newborn child, a DNA test using them is carried out after the birth of a child. Typically, a DNA test is performed within 14 days. If an urgent result is required, the test is carried out 3 days in advance. Some laboratories provide home DNA testing service. The data obtained as a result of home DNA analysis cannot be provided as evidence in court, but will help to dispel, or vice versa, to confirm the doubts of one of the child's parents.Home DNA test to determine paternity
To conduct a home paternity determination, you need to contact the laboratory that provides this service. From the laboratory, you will be sent a set with the necessary tools for the collection of biological material, as well as detailed instructions for its use. After collection, the biological material is sent by mail to the laboratory, where DNA testing is carried out. As a rule, the results come 3 days after the material is received by the laboratory.Is it possible to accurately determine paternity before the birth of a child?
In cases where paternity must be established even before the birth of a child, DNA testing is used using biological materials of the fetus, which can be obtained as follows:- Chorionic villus sampling is performed at term. To obtain the biological material of the fetus, the doctor, under the control of an ultrasound machine, inserts a needle through the vagina or the anterior abdominal wall, reaching the fetal membrane (chorion). The risk of termination of pregnancy as a result of this procedure is less than 1%.
- Amniocentesis is a procedure for obtaining amniotic fluid (amniotic fluid) for genetic testing. Amniocentesis can be performed at term. The procedure for taking amniotic fluid is carried out by a gynecologist: under the control of an ultrasound machine, the doctor inserts a long thin needle through the skin of the anterior abdominal wall, penetrates the uterus and takes the required amount of amniotic fluid for examination. The risk of complications and spontaneous termination of pregnancy as a result of amniocentesis is less than 1%.
- Cordocentesis is performed at a gestational age of more than -20 weeks. During cordocentesis, fetal blood is taken from the vessels of the umbilical cord. The risk of complications of this method is also less than 1%.
When doubts arise about paternity, they turn to those options according to which it is allowed to challenge it. prescribes that it is allowed to appeal against parental status in court when evidence is provided. The main way to appeal paternity is to do a DNA test. Without him, it is difficult to dispute the status of the father, but it is permissible.
How to challenge paternity?
The following persons can dispute parental status:
- mother or father of the child, recorded in the birth certificate;
- person who is the de facto parent;
- child upon reaching the age of majority.
Statistics show that up to 30% of fathers are not raising their children. Half of them don't know about it. The initial step when in doubt is to talk to your wife. The option requires a certain tact and delicacy and is not always implemented without prejudice to the relationship.
DNA testing makes things easier. According to Russian law, the procedure is allowed to be carried out without the consent of the spouse. If DNA tests confirm the absence of parental status, they go to court.
Certain situations do not allow paternity to be challenged even by DNA:
- with artificial insemination or surrogacy;
- if the parent knew that the child was not his at the time of his registration.
The second option implies that the person deliberately formalizes parental status over someone else's child. It is not allowed to challenge such a decision in the future.
What is needed for this?
To challenge paternity by DNA analysis, a lawsuit is filed in court. It is accompanied by evidence of paternity, as well as the grounds on which it should be appealed.
Evidence the appeal may be:
- documents indicating separation during the period of conception;
- witness's testimonies;
- medical certificates, DNA examination and other evidence of parental status.
To challenge paternity in court, they provide list of documents:
- statement of claim for appeal in duplicate;
- a copy of the child's birth certificate together with the original;
- copy of marriage or divorce certificate;
- receipt of payment of state duty;
- documentary evidence.
Statement of claim is drawn up by the plaintiff according to certain criteria:
- the name of the judicial institution is fully prescribed;
- full details of the plaintiff and the defendant - names, place of residence and registration of each of the parties, telephone numbers, other contact information;
- if there are representatives - their data, as well as the details of the notarized power of attorney, a copy of it is attached to the list of documents;
- the presence of a marriage is prescribed, when and where it was registered;
- data on the child's birth certificate are registered;
- the requirement to recognize the invalidity of the parental status is given, the grounds are indicated - DNA examination, other aspects.
Can you argue without DNA?
DNA analysis provides reliable information about parental status. Its implementation is based on the following aspects:
- the analysis requires the biomaterial of the child and parent;
- the procedure is affordable, but expensive;
- in the absence of a medical examination, the court may oblige to pass it.
In certain situations, it is extremely difficult for a father to carry out such an analysis - separation from the child, lack of money, or other moments. Challenge paternity without DNA testing in the following ways:
- documentary evidence of separation during the alleged conception;
- calculation by blood group - certain combinations have an extremely low chance of occurrence or cannot occur at all, for example, with the first blood group, both parents cannot have a different group for the child.
The need to challenge paternity without a DNA test can also arise after a divorce. The legislation provides that a child born into the world within 10 months after the break of official relations, it is registered with the ex-spouse. In such a situation, it is relevant to provide documentary and evidence information about separation.
Where to contact?
The question of which court to apply to is easy to solve. The statement of claim is filed to the district court... The review procedure does not specify the time frame within which a decision is made. The process can take years, especially if done without DNA testing.
Term, during which it is allowed to challenge paternity, by law not limited... The child is allowed to appeal the parental status of his father upon reaching the age of majority. In case of incapacity, a guardian or curator may file a claim.
Pregnancy calculators
If you are faced with a difficult choice and want to find out who is the father of your unborn child, the interactive Promptor will help you figure it out.
If you have a short time frame, then in order to narrow the circle of suspected paternity as much as possible, you will have to remember a few numbers. First, you need to remember when your last period began. And secondly, what is your average cycle (the period between the beginning of the penultimate and the beginning of the last menstruation)... Fill out the form and click "Next".
A bit of theory to better understand the logic of the interactive Prompt.
The most favorable day for conception is the day of ovulation. On this day, an egg is released. And if unprotected sexual intercourse occurs on the day of ovulation, sperm full of strength rush to meet the "fresh" egg.
The life path of an unfertilized egg ends in a couple of days. Therefore, sex two days after ovulation rarely leads to pregnancy. In sperm cells, the strength is also not unlimited, they can "wait" for an egg for five days, no more. For this reason, unprotected intercourse more than five days before ovulation is also considered relatively “safe”. The calendar method of contraception is based on this (not very reliable).
When does ovulation occur?
The average woman begins her period two weeks after ovulation. In other words, ovulation occurs 14 days before your expected period.
Who is the father of the child?
It is absolutely possible to establish whether a man is the father of a child using a DNA test. But this can only be done when the child is born.
How to find out who is the father of a child without a DNA test and even during pregnancy? You can ask the doctor after the next examination or ultrasound.
If you remember the day of the beginning of the last menstrual period and the average duration of the cycle, you can yourself try to determine who the baby is from. This method does not give an absolute guarantee, but it often helps to understand the origin of pregnancy.
Questions to the article
Menstruation, came a day earlier, went 6 days, cycle 27-30 days, after ...
Ovulation on the 17th day of the cycle approximately comes ... the cycle, after all, I have ...
Conception. The last month was 08/28/2017, a cycle of 28-30 days. First...
What is the most likely number that I got pregnant? ...
There was sex with a PP. On which of these days could pregnancy occur!? ...
My period has gone. I have a husband with whom we are planning a child and in ...
In January 2017, I went to the gynecologist for pregnancy tests ...
Monthly, i.e. On the 24th there was intercourse, with a condom, on the 28th there was ...
My partner was the interrupted act of 01.12, and with the second, the permanent one, with ...
Irregular cycle after oral contraceptive, 26-30 days. 04/05/2016 ...
After 19.05 months came. 06/01 was on an ultrasound scan on the issue of cystitis, they put ...
The interrupted act was on 31.03, 2.04, 4 and 5.04. Last months from 14.04. - 20.04 ....
The fact that I cannot remember when the last M was (lost ...
The man was 03/17/16 then sexual intercourse with another young man ...
Menstruation in March was 03/16/16) and sexual intercourse on 04/21/2016. The doctor says that ...
On the same day, she had intimacy with her husband, sex was not protected. these 2 ...
Days). After there was a sexual intercourse with a boy, let's call him M, but 1 ...
Monthly 12-16.05.2016. Cycle 29-31 days. Sexual intercourse was at 13.05; 05/31/2016 Uzi ...
ONE, INTERRUPTED SEX ACT 12.05.2016 WITH ANOTHER, BY WHAT NUMBER OF ...
Could you get pregnant? ...
Measurement of basal temperature. The last M from 06/28/16 to 07/06/16. with...
02.01.2016. CTD by ultrasound from 02/04/2016 8mm, from 03/14/2016 60mm. What number is the most ...
Interrupted intercourse on 15.08., Full-fledged sexual intercourse on 17.08. ...
Who is the father of the child? ...
Delivered 13.1 weeks. ktr 67.8mm. Sexual acts were 04/22/16. and 04/30/2016 ....
17:00, 06/29/2016 intercourse at 12 o'clock in the morning. 07/09/2016 ultrasound of the ovum is not ...
A week. As far as I understand, conception took place at the end of December ...
5.days, 05.06. unprotected sexual intercourse, 23.06. The test showed bright two ...
Menstruation. 8.06 was an unprotected act and 10.06 was an unprotected act ...
Monthly came 2 days later, it turns out the cycle of 30 days was ...
Pregnancy certificate. In which the last menstruation is indicated ...
There is no question of who can be the father of the child. But with one ...
It was our last meeting, we parted. There was a period in ...
According to words without ending, in the subsequent permanent relationship with ...
I had unprotected intercourse with my boyfriend, 14 ...
And the last one was with a cycle of 29 and 32 days. PPA was 11/17/2015 with one ...
I was with my beloved 5.12. , 7.12., Menses expected 8.12. But it happened ...
There were 10/01/2015 to 10/05/2015, sexual intercourse was 09/26/2015 and 10/03/2015 on 03/01/2016 ...
This applies not only to quantitative traits, such as height, but also to qualitative ones, such as hair and eye color. It used to be believed, for example, that blue-eyed parents cannot have a brown-eyed child, but this is not the case either. It was necessary to find such characters that are quite easily determined and strictly obey the laws of heredity, which have not one or two, but several independent variants that are found in different people.
How to find out who the father of a child is: 4 ways to determine paternity without DNA
The rest are Rh-negative. A mother and father with a positive Rh factor can have a child with both a positive and a negative parameter.And parents with a negative Rh factor will always have children with a Rh negative factor. They are caused by mutations in a gene. If in the mother's family the disease manifested in the child was not observed, while the potential father or his closest blood relatives have this disease, then this fact is an indirect confirmation of paternity.
How to find out who is the father of a child without DNA
He will answer with 99.9% accuracy. 0.1% is always left for margin of error. Alternatively, you can try to determine from whom the child was conceived by the blood type of his and the alleged father.To do this, you need to use special tables for comparing blood groups and check. If you do not resort to laboratory examinations, then it is possible to determine paternity by external signs.
Possible options for determining paternity without DNA: - try to calculate the day of pregnancy.
All about determining paternity
Methods for establishing paternity differ in the degree of complexity, reliability of the results and the value of the data obtained in terms of the possibility of their use as evidence in court. Below are the most well-known methods for determining paternity: External signs such as eye color, hair and skin color, facial similarity, etc.cannot serve as a reason for confirming or refuting paternity.
How to determine paternity by external signs
This applies not only to quantitative traits, such as height, but also to qualitative ones, such as hair and eye color. It used to be believed, for example, that blue-eyed parents cannot have a brown-eyed child, but this is not the case either.It was necessary to find such characters that are quite easily determined and strictly obey the laws of heredity, which have not one or two, but several independent variants found in different people.
How to identify paternity without DNA
If the mother dies, disappears, or was deprived of parental rights, the father prepares a joint declaration of paternity with the guardians or with the child upon reaching the age of majority. a man refuses a child born in marriage; the man wants to recognize a child born out of wedlock as his own; a woman demands child support from his father, who does not recognize his offspring; other.Determination of paternity - description of methods
Often, in the event that during one menstrual cycle a woman has had sexual intercourse with several men, it becomes necessary to establish paternity. In such situations, for the purpose of a preliminary and very inaccurate determination of paternity, you can try to calculate a specific date on which the maximum chance of conception fell. Accordingly, a man who has had sexual intercourse with a woman shortly after, or before that date, has a high probability of being the father of the child.Establishing relationship based on appearance
The noted pattern (children and grandparents) is also traced in other children. Belonging to different races of the father and mother, as a rule, facilitates the comparison of a whole complex of signs: the shape of the eyes, the color of the hair, eyes and skin, etc.For example, the father is a Mongoloid, the mother is a Caucasian, the child may have an epicanthus, an oblique inner eye section, etc.
Intermediate appearance in mestizo usually does not occur earlier than after 2 - 3 generations.
In addition, it is not uncommon for children to be born completely similar to their mother or grandmother; accordingly, there can be no question of any definition of the relationship between the child and the father. By the date of conception and the duration of pregnancy, some incredulous daddies are trying to figure out whether they are involved in the toddler or not.
In this case, nature can play a cruel joke with men. The fact is that sperm cells can remain viable for up to 5-7 days, so if a woman had intimacy with another man a few days before ovulation, and with the declared father on the day of ovulation, then the probability of relationship with a child is the same for both partners.
thanks
Establishing paternity involves a series of procedures that are aimed at determining the relationship between a child and a man, presumably being his biological father.
Medicine operates with several basic methods of determining paternity. They differ in the technique and degree of complexity, in the materials used in the process, and, of course, in the reliability of the results obtained. As a rule, research related to the establishment of paternity is carried out by genetic doctors. In doing so, they use the following methods:
- by date of conception and gestational age;
- by external signs;
- for DNA analysis.
Determination of paternity by date of conception and gestational age
By date of conception
Often, in the event that during one menstrual cycle a woman has had sexual intercourse with several men, it becomes necessary to establish paternity. In such situations, for the purpose of a preliminary and very inaccurate determination of paternity, you can try to calculate a specific date on which the maximum chance of conception fell. Accordingly, a man who has had sexual intercourse with a woman shortly after, or before that date, has a high probability of being the father of the child.It is known that if a woman has a regular menstrual cycle, then the maximum probability of conception occurs in the middle of the menstrual cycle, about 14-15 days from the beginning of the next menstruation. But as practical observations show, the moment of the maximum probability of conception in many women is difficult to determine precisely.
Establishing paternity by comparing the possible date of conception and the date of sexual intercourse may be incorrect for another reason. The fact is that sperm cells can maintain their activity and the ability to fertilize in the female body for 3-5 days after intercourse. This means that conception could have occurred a few days after sexual intercourse. In this case, the father of the child may be a man who had intercourse with a woman a few days before the optimal date for conception. A similar situation is possible even if a woman had sex directly on the date of conception with another man.
By gestational age
Establishing paternity is also possible by determining the gestational age, which can be roughly measured according to the indications of an ultrasound scan. However, even the most advanced ultrasound equipment is not able to establish the date of conception with high accuracy, and indicate a specific date.Thus, establishing paternity based on determining the possible date of conception or measuring the gestational age is an extremely approximate and unreliable method. It can only have a complementary meaning. In addition, this technique becomes practically useless if a woman has had sexual intercourse with various partners for a short period of time.
Determination of paternity by external signs
Various elements of a person's appearance, such as color of hair, eyes or skin, similarity in facial features, etc., can only serve as an indirect and very unreliable reason for refuting or confirming paternity. This is explained by the fact that, although external signs are set genetically, they can vary widely and have a different degree of manifestation in each case. In addition, the inconsistency of the method of establishing paternity based on the external similarity of a man and a child is confirmed by the fact of the existence of twins. This is the name of people who do not have any family ties, but at the same time are very similar to each other in their appearance.
Determination of paternity by blood group
There are more than 20 different blood group systems in the human population. The most commonly used are only two of them:1. System AB0. Most often it is this system that is meant when they talk about the "blood group".
2. Rh factor. Differences in blood Rh factor.
Both of these blood grouping systems are genetically defined and, therefore, open up some possibilities for determining paternity. The very principle of establishing paternity according to the Rh factor and blood group is based on the fact that the parameters of the child's blood depend on the set of genes that the mother and father will pass on to him.
AB0 system
In this system, 4 blood groups are distinguished:- I or 0 (zero);
- II - A;
- III - B;
- IV - AB.
Determination of paternity based on blood group cannot be considered an accurate method, although it is more reliable than those described above. This technique is considered rather indicative, and is used as a screening preliminary study before conducting a DNA test. A blood test only rarely provides conclusive evidence. For example, if the child has a blood group I, and the father has an IV.
Rh factor
According to the system of Rh-factors, only two groups are distinguished - Rh-negative (Rh-) and Rh-positive (Rh +). Accordingly, their difference lies in the presence or absence of specific antibodies (Rh factor) in human blood.Establishing paternity based on the Rh factor is less reliable than on the basis of the AB0 system. Even Rh-positive parents can have a baby with Rh-negative blood. However, in Rh negative parents, the child will also always have a negative Rh factor. Therefore, the only case when it can be unambiguously asserted that a man is not the biological father of a child arises in a situation where both parents have a negative Rh factor, and the child is positive.
Determination of paternity by blood group serves as a preliminary method for assessing the presence of consanguinity between a child and a man. The peculiarity of this method lies in the fact that a negative result will be 99% accurate, and a positive one is practically insignificant. In addition, this analysis can be carried out only after the birth of a child, when it becomes possible to examine his blood group.
Determination of paternity by DNA
Sometimes situations arise in life when it is necessary to establish the degree of kinship of people with a sufficient degree of reliability. This includes cases that are related to family reunification, solving various legal problems, investigating tissue compatibility, etc. Only a few decades ago, such a problem was solved with enormous difficulties and extremely dubious reliability of the results. But after biologists learned to decipher the DNA code, methods of genetic research were created, which make it possible to answer with high accuracy the question of whether there is a biological relationship between two people. Including similar technologies are used in determining paternity. Each person carries completely unique genetic information. It is encoded in DNA (deoxyribonucleic acid). These giant molecules are found in every cell in the human body that has a nucleus. DNA molecules are organized into complex structures called chromosomes.
Each of the chromosomes is contained in each of the somatic cells in duplicate. The Greek word "soma" means "body", therefore the cells that make up the human body are called somatic. The only exception - non-somatic cells - are reproductive cells: sperm in men and eggs in women. They differ from somatic ones in that they contain all chromosomes not in pairs, but only in the singular.
Why did nature provide for such a distinction? As you know, during conception, the sperm and the egg merge and their chromosome set, that is, the genetic material that they contain, merges. The child receives one chromosome from each pair from the father (sperm chromosome), and the second from the mother (egg chromosome). In this way, the child receives a complete chromosome set, and inherits the genetic material of his parents - therefore, he often looks like them. But on the other hand, combinations of male and female chromosomes can add up to billions of different variants - this is what determines the individuality of each person.
DNA analysis to determine paternity
This method is based precisely on this duality of the child's DNA: on the one hand, it is unique in its own way, on the other, it arose as a result of a combination of parts of the mother's and father's DNA. Modern technologies of molecular genetic research allow doctors to identify the maternal and paternal components of DNA in any person. In addition, it is possible to trace the transmission of certain DNA fragments in mother-child or father-child pairs. Indeed, in the case of confirmation of kinship, the DNA fragments in the compared pairs coincide almost completely.Legal significance
A DNA test for determining paternity is considered so reliable that its results even have official legal force. According to the Order of the Ministry of Health, to prove the fact of paternity, it is sufficient to conduct a study with an accuracy of the results of 99.90%. Modern technology makes it possible to achieve even greater accuracy, but more often than not this is simply not necessary. The correctly calculated probability of paternity, equal to 99.90%, is quite sufficient to use the formulation accepted in the scientific world and legal practice: "paternity is practically proven." The exclusion of the fact of paternity in order to recognize it as legally significant requires obtaining at least three mismatches between the investigated DNA fragments of the child and his alleged father.
It should be remembered that without material taken from the child's mother, it is more difficult to achieve the level of required reliability of the study than in the case of testing all family members. That is why, if a DNA examination is carried out in order to challenge or determine paternity in court, then judges often insist on the simultaneous collection of materials from the child, his alleged father and biological mother. This is necessary to ensure that the report issued by the forensic medical expert does not raise any doubts.
Determination of paternity using the study of DNA molecules is an opportunity to obtain a completely reliable and scientifically substantiated result. This conclusion can become an important argument in solving many legal problems, for example, in divorce proceedings and the recovery of alimony, determination of heirs and distribution of inheritance, in immigration and many other issues.
How is the conclusion formulated for DNA analysis to determine paternity?
After conducting a DNA analysis to establish paternity, a conclusion is issued containing one of the following conclusions:1. The result is positive- the man is NOT EXCLUDED as the biological father of this child (the probability of paternity is 99.9%).
2. The result is negative- the man is EXCLUDED as the biological father of this child (the probability of paternity is 100% excluded).
Theoretically, it is possible for another person to exist in the world with a genetic makeup that is absolutely identical to the genetic passport of the person being tested. For example, this situation is observed in identical twins, whose genetic material matches each other 100%. This probability is associated with a small deviation from a completely reliable positive result in a DNA paternity test. But, in the overwhelming majority of cases, establishing paternity with a probability of 99.9% will mean that it is proven. And a negative result with the correct sampling of material and the correct conduct of the study is always unambiguously correct.
What biological materials can be used for DNA analysis to determine paternity?
DNA molecules can be isolated from many different sources. Previously, only blood taken from a vein was used to determine paternity by DNA. However, such blood samples should be taken only by a qualified medical professional, and in a hospital or at least a polyclinic. For many clients, and especially for children, this method is not always acceptable. Today, the range of materials for DNA research has expanded tremendously. Now it is possible to perform DNA analysis not only for blood from a vein, but also for hair, saliva, nails, etc.Buccal epithelium
Currently, the most preferred, easy and common method of obtaining a reference sample for examination is the use of a buccal (buccal) smear. In this case, for genetic analysis, epithelial cells of the oral mucosa are used, which are taken on the inner side of the cheek with a cotton swab. This is a non-invasive (that is, not injuring body tissues) and absolutely painless method, in which the sampling of the material takes about a minute. In addition, it does not require the presence of medical workers, and can be performed by the patient himself at a time when it is convenient for him, without even leaving home. Also, the use of buccal epithelium reduces the likelihood of contamination of the test material. DNA test for determining paternity by non-standard samples
If the collection of the buccal epithelium is not possible or difficult, then you can use other methods. Almost any object containing human DNA can be used as a source of DNA when performing private and anonymous studies, in addition to a standard sample of buccal epithelium:- blood samples;
- saliva;
- teeth;
- nails;
- sperm;
- samples from the tissue biopsy store;
- root hair and other suitable biological tissues.
- toothbrushes;
- razor blades;
- cigarette butts;
- handkerchiefs;
- napkins;
- clothes, etc.
In addition, despite the use of the most modern methods of genetic examination, it is impossible to isolate DNA from such non-standard samples in some cases due to its complete absence.
DNA analysis to determine paternity
The control tissue sample is thoroughly analyzed to create a DNA profile of the person. Subsequently, this DNA profile is compared with another sample in order to identify genetic similarities.Polymerase chain reaction
To create a DNA profile of a person, it is not enough just to isolate deoxyribonucleic acid from the provided material. The research will be successful only if there are enough DNA molecules, that is, a fairly large number. For this purpose, a process called polymerase chain reaction is used. This reaction multiplies or amplifies the DNA sample that was isolated from the starting material. As a result, several billions of absolutely exact copies of the same DNA obtained from a person are obtained. Geneticists are already working with this number of DNA molecules.Study of loci
A DNA locus is a strictly defined part of it, which is subjected to research and comparison. 99.9% of the sequences found in human DNA are the same in composition, but, nevertheless, the DNA of different people carries a sufficient number of individual differences. There are parts of the DNA molecule that are unique to each person. It is this fact that determines the differences between us.The accuracy of DNA analysis is primarily influenced by the number of studied genetic loci. The more sites that define our uniqueness will be investigated, the higher the likelihood of denial or confirmation of paternity. At present, it is customary to analyze from 16 to 40 different loci on each DNA sample. This provides more than 99.99% confidence when biological paternity is confirmed, and 100% when excluded. In addition, the analysis is often carried out by two independent research teams, and the data obtained are subsequently verified. This procedure avoids errors associated with accidental contamination of the material, or inaccuracies when working with it.
Determination of paternity during pregnancy
Establishing paternity in early pregnancy is traditionally a prenatal diagnosis. To determine paternity during pregnancy, it is first necessary to collect biological material from the fetus. This procedure is strictly recommended to be carried out only in a specialized medical institution, since it may be associated with possible risks of complications. In a situation where paternity must be determined even before the birth of a child, DNA testing is used based on biological materials of the fetus, which are obtained as follows:
- Chorionic villus biopsy. The material is taken from 9 to 12 weeks of pregnancy. In order to obtain biological material, a specialist, under the control of an ultrasound machine, inserts a needle through the front wall of the abdomen or vagina, reaching the fetal membrane. The chance of terminating a pregnancy during this procedure is about 2%.
- Amniocentesis. The procedure for obtaining amniotic fluid (amniotic fluid) for subsequent genetic research. Amniocentesis is most often performed between 14 and 20 weeks of gestation. The procedure for collecting amniotic fluid is carried out by a specialist gynecologist. He, under the control of an ultrasound machine, through the tissues of the anterior abdominal wall, introduces a thin and long needle, penetrates through the wall of the uterus, and collects the amount of amniotic fluid required for the study. The chance of complications or spontaneous abortion during amniocentesis is about 1%.
- Cordocentesis. In the process of cordocentesis, fetal blood is taken directly from the vessels of the umbilical cord. This procedure is performed at a gestational age exceeding 18-20 weeks. The chance of complications with this method is less than 1%.
Non-invasive Prenatal Paternity Test Technique
According to American scientists, they have developed a non-invasive method for determining paternity during pregnancy. Genetic examination is performed using a special technique in which a small amount of DNA is analyzed. This test can be used already in the first trimester, most often after the 10th week of pregnancy. An earlier analysis does not guarantee that a sufficient amount of fetal DNA is obtained from the mother's blood plasma. Testing is carried out by examining a number of venous blood samples taken from the expectant mother and the alleged father.In the technology of prenatal non-invasive determination of paternity, the study of the freely circulating DNA of the fetus is used. A certain amount of it during pregnancy is in the blood of the expectant mother. Modern technologies used in genetics make it possible to isolate it and compare it with the DNA of the mother and possible biological father.
The new non-invasive paternity test can replace the above methods of determining the DNA profile of the fetus, which are unsafe for the health of the mother and child. According to scientists, it has the same high accuracy, but it is more preferable, since during its implementation there is no threat of complications and early termination of pregnancy.
Conclusion
The minimum period for establishing biological relationship and conducting research to determine paternity is 3 days. However, in most cases, for a qualitative analysis it will take from ten days to two weeks from the moment the biological materials arrive at the laboratory.Today, DNA analysis can be done almost anywhere. There are even portable laboratories. And equipment for genetic identification of a person is produced by dozens of enterprises in many countries of the world. That is why the previously complicated and exotic procedure is now becoming a common research method that anyone can use.
Before use, you must consult a specialist.