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DNA paternity testing

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DNA paternity testing uses DNA profiles to determine whether an individual is the biological parent of another individual. Paternity testing can be especially important when the rights and duties of the father are in issue and a child's paternity is in doubt. Tests can also determine the likelihood of someone being a biological grandparent. Though genetic testing is the most reliable standard, older methods also exist, including ABO blood group typing, analysis of various other proteins and enzymes, or using human leukocyte antigen antigens. The current paternity testing techniques are polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP). Paternity testing can now also be performed while the woman is still pregnant from a blood draw.[1][2]

DNA testing is currently the most advanced and accurate technology to determine parentage. In a DNA paternity test, the result (called the 'probability of parentage)[3] is 0% when the alleged parent is not biologically related to the child, and the probability of parentage is typically 99.99% when the alleged parent is biologically related to the child. However, while almost all individuals have a single and distinct set of genes, rare individuals, known as "chimeras", have at least two different sets of genes. This can lead to complications during DNA analysis, such as false negative results if their reproductive tissue has a different genetic make-up from the tissue sampled for the test.[4]

Paternity or maternity testing for child or adult

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The DNA test is conducted by collecting buccal (cheek) cells found on the inside of a person's cheek using a buccal or cheek swab. These swabs have handles make of wood or plastic with a cotton synthetic tip. The collector rubs the inside of a person's cheek to collect as many buccal cells as possible, which are then sent to a laboratory for testing. Samples from both the alleged father or mother and the child are required for the test.

Prenatal paternity testing for unborn child

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Invasive prenatal paternity testing

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It is possible to determine who the biological father of the fetus is while the woman is still pregnant through a procedure known as chorionic villus sampling or amniocentesis. Chorionic villus sampling retrieves placental tissue, which can be done either through the cervix (transcervical) or the adbominal wall (transabdominal). Amniocentesis involves collecting amniotic fluid by inserting a needle through the pregnant mother's abdominal wall. Both procedures are highly accurate because they obtain samples directly from the fetus. However, there is a small risk of misscarriage associated with them, which could result in the loss of the pregnancy. Both CVS and amniocentesis require the pregnant woman to consult a maternal-fetal medicine specialist who will perform the procedure.

Non-invasive prenatal paternity testing

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Recent advances in genetic testing have led to the ability to identify the biological father while the woman is still pregnant. A small quantity of cell-free fetal DNA (cffDNA) is present in the mother's blood during pregnancy. This allows for accurate paternity testing during pregnancy from a blood draw without any risk of miscarriage. Research indicates that cffDNA can first be detected as early as seven weeks into the pregnancy, and its quantity increases as the pregnancy continues.[5][6]

DNA profiling

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Example of DNA profiling in order to determine the father of a child (Ch). Child's DNA sample should contain a mixture of different size DNA bands of both parents. In this case, person #1 is likely the father.
Main article: DNA profiling

The DNA of an individual is identical in all somatic (nonreproductive) cell. During Sexual reproduction, the DNA from both parents combine to create a unique genetic makeup in a new cell. As a results, the genetic material of an individual is derived equally from each parent. This genetic material is reffered to as the nuclear genome because it is located in the nucleus of a cell.

Autosomal DNA testing allows for a comparison between the child’s DNA, the mosther’s DNA, and the alleged father’s DNA. By examining the genetic contribution from the mother, researchers can determine possible genotypes for the actual father. Specific sequences are examined to see if they were copied verbatim from one individual's genome; if so, then the genetic material of one individual could have been derived from that of the other (i.e. one is the parent of the other). If the alleged father cannot be excluded as the true father, then statistical analysis can be preformed to assess how likely it is that the alleged father is the true father compared to a random man.[7]

In addition to nuclear DNA, mitochondria contain their own genetic material known as mitochondrial DNA. This mitochondrial DNA is inherited soley from the mother and is passed down without any mixing. As a results, establishing a relationship through the comparison of the mitochondrial genome is generally easier than doing so with the nuclear genome. However, testing the mitochondrial DNA can only confirm wheather two individuals share a maternal ancestry; it cannot be used to determine paternity. Therefore, its application is somewhat limited.

In testing the paternity of a male child, the Y chromosome can be used for comparison, as it is inherited directly from father to son. Like mitochondrial DNA, the Y chromosome is passed down through the paternal line. This means that two brothers share the same Y chromosome from their father. Therefore if one brother is the suspected father, his biological brother could also be the father based solely on Y chromosomal data. This holds true for any male relative related to the suspected father along the paternal line. For this reason, autosomal DNA testing would provide a more accurate method for determining paternity. [8]

In the US, the AABB has established regulations for DNA paternity and family relationship testing, although AABB accreditation is not mandatory. DNA test results can be considered legally admissible if the collection and processing adhere to a proper chain of custody. Similarly in Canada, the SCC has regulations on DNA paternity and relationship testing, while accreditation is recommended, it is not required.

The Paternity Testing Commission of the International Society for Forensic Genetics is responsible for creating biostatistical recommendations in accordance with the ISO/IEC 17025 standards.[9] Biostatistical evaluations of paternity should be based on the likelihood ratio principle, resulting in the Paternity Index (PI). These recommendations offer guidance on the concepts of genetic hypotheses, calculation concerns necessary for producing valid PIs, as well as adressing specific issues related to population genetics.

History

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The first form of parental testing involved blood typing, which began in the 1920s. The technique emerged after scientist discovered blood types, first identified in 1901, are genetically inherited. In blood typing, the blood types of the child and the alleged parents are compared to assess the possiblity of a parental linkage. For instance, two parents with type O blood can only have a child with an type O blood, while two parents with type B blood can produce a child with either type B or type O blood. However, this method often resulted in inconclusive outcomes, as approximately 30% of the population could be excluded from being the potential parents based on blood type alone.[10] In the 1930s, serological testing was introduced, examing specific proteins in the blood, and this method had a slightly high exlusion rate of 40%.[11]

In the 1960s, accurate genetic paternity testing became feasable with the development of HLA typing, which compares the genetic fingerprints found in white blood cells of the child and alleged parent.[12] HLA tests could achieve an accuracy of 80%, but they are unable to distinguish between close relatives.[13] The technology for genetic parental testing advanced further in 1970 with the isolation of the first restriction enzyme. By the 1980s, highly accurate DNA paternity testing became available with the introduction of RFLP(Restriction Fragement Length Polymorphism. In the 1990s, PCR (Polymerse Chain Reaction) emerged as the standard method for DNA paternity testing. This method is simpler, faster, and more accurate than RFLP, boasting an exclusion rate of 99.99% or higher.[13]

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A DNA parentage test that adheres to a strict chain of custody can produce legally admissible results used for various purposes, including child support, inheritance, social welfare benefits, immigration, and adoption. To meet the chain-of-custody legal requirements, all tested individuals must be properly identified, and their specimens must be collected by an independent third-party who is not related to any of the tested parties and has no interest in the test’s outcome. The quantum of evidence needed is clear and convincing evidence, meaning that it is more substancial than in an ordinary civil case but less than the “beyond a reasonable doubt” standard needed for a criminal conviction.

In recent years, immigration authorities in multiple countries- including the United States, United Kingdom, Canada, Australia, France, and others, may accept DNA parentage test results from immigration petitioners and beneficiaries in a family-based immigration case when primary documents that prove biological relationship are missing or inadequate.[14]

In the U.S., it is the responsibility of immigration applicants to arranging and cover the cost for DNA testing. U.S. immigration authorities mandate that any DNA test performed must be conducted by a laboratory accredited by the AABB (formerly American Association of Blood Banks)[15]. Similarly, in Canada, the laboratory must be accredited by the Standards Council of Canada.

Although paternity tests are more prevalent than maternity tests, there are situations where the biological mother of the child is uncertain. Examples include cases in which an adopted child seeks to reunite with their biological mother, potential hospital mix-ups, and in vitro fertilization scenarios where an unrelated embryo may have been implanted in the mother.

Other factors, such as new laws regarding reproductive technologies involving donated eggs and sperm or surrogate mothers, can also complicate the determination of legal motherhood. For instance, in Canada, the federal Human Assisted Reproduction Act allows for the use of hired surrogate mothers, meaning that the legal mother may be the egg donor, rather than being the women who gave birth. Similar laws exist in the United Kingdom and Australia.

In Brazil in 2019, two male identical twins were ordered to both pay maintenance for a child fathered by one of them, because the father could not be identified with DNA.[16]

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Australia

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Peace-of-mind parentage tests are widely available on the internet. For a parentage test (paternity or maternity) to be admissible for legal purposes, such as for changing a birth certificate, Family Law Court proceedings, visa/citizenship applications or child support claims, the process must comply with the Family Law Regulations 1984 (Cth).[17] Further, the laboratory processing the samples must be accredited by the National Association of Testing Authorities (NATA).[18]

Canada

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Personal paternity-testing kits are available. The Standards Council of Canada regulates paternity testing in Canada whereby laboratories are ISO 17025-approved. In Canada, only a handful of labs have this approval, and it is recommended that testing is performed in these labs. Courts also have the power to order paternity tests during divorce cases.[19]

China

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In China, paternity testing is legally available to fathers who suspect their child is not theirs. Chinese law also requires a paternity test for any child born outside the one-child policy for the child to be eligible for a hukou, or family registration record. Family tie formed by adoption can also only be confirmed by a paternity test. A large number of Chinese citizens seek paternity testing each year, and this has given rise to many unlicensed illegal testing centers being set up.[20]

France

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DNA paternity testing is solely performed on decision of a judge in case of a judiciary procedure in order either to establish or contest paternity or to obtain or deny child support.[21] Non consensual private DNA paternity testing is illegal, including through laboratories in other countries, and is punishable by up to a year in prison and a €15,000 fine.[22] The French Council of State has described the law's purpose as upholding the "French regime of filiation" and preserving "the peace of families."[23]

Germany

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Under the Gene Diagnostics Act of 2009, secret paternity testing is illegal. Any paternity testing must be conducted by a licensed physician or by an expert with a university degree in science and special education in parentage testing, and the laboratory carrying out genetic testing must be accredited according to ISO/IEC 17025. Full informed consent of both parents is required, and prenatal paternity testing is prohibited, with the exception of sexual abuse and rape cases. Any genetic testing done without the other parent's consent is punishable with a €5,000 fine.[24] Due to an amendment of the civil law section 1598a in 2005, any man who contests paternity no longer automatically severs legal rights and obligations to the child.[25][26]

Israel

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A paternity test with any legal standing must be ordered by a family court. Though parents have access to "peace of mind" parental tests through overseas laboratories, family courts are under no obligation to accept them as evidence. It is also illegal to take genetic material for a parental test from a minor over 16 years of age without the minor's consent. Family courts have the power to order paternity tests against the will of the father in divorce and child support cases, as well as in other cases such as determining heirs and settling the question involving the population registry. A man seeking to prove that he is not the father of the child registered as his is entitled to a paternity test, even if the mother and natural guardian object. Paternity tests are not ordered when it is believed it could lead to the murder of the mother, and until 2007, were not ordered when there was a chance that the child of a married woman could have been fathered by a man other than her husband, thereby making the child a mamzer under Jewish law.[27][28][29]

Philippines

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DNA paternity testing for personal knowledge is legal, and home test kits are available by mail from representatives of AABB- and ISO 17025-certified laboratories.[30] DNA Paternity Testing for official purposes, such as sustento (child support) and inheritance disputes, must follow the Rule on DNA Evidence A.M. No. 06-11-5-SC, which was promulgated by the Philippine Supreme Court on October 15, 2007.[31] Tests are sometimes ordered by courts when proof of paternity is required.

Spain

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In Spain, peace-of-mind paternity tests are a "big business," partly due to the French ban on paternity testing, with many genetic testing companies being based in Spain.[32][33]

United Kingdom

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In the United Kingdom, there were no restrictions on paternity tests until the Human Tissue Act 2004 came into force in September 2006. Section 45 states that it is an offence to possess without appropriate consent any human bodily material with the intent of analysing its DNA. Legally declared fathers have access to paternity-testing services under the new regulations, provided the putative parental DNA being tested is their own. Tests are sometimes ordered by courts when proof of paternity is required. In the UK, the Ministry of Justice accredits bodies that can conduct this testing. The Department of Health produced a voluntary code of practice on genetic paternity testing in 2001. This document is currently under review, and responsibility for it has been transferred to the Human Tissue Authority. In the 2018 case of Anderson V Spencer the Court of Appeal permitted for the very first time DNA samples taken from a Deceased person to be used for paternity testing.

United States

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In the United States, paternity testing is fully legal, and fathers may test their children without the consent or knowledge of the mother. Paternity testing take-home kits are readily available for purchase, though their results are not admissible in court and are for personal knowledge only.

Only a court-ordered paternity test may be used as evidence in court proceedings. If parental testing is being submitted for legal purposes, including immigration, testing must be ordered through a lab that has AABB accreditation for relationship DNA testing.[34]

The legal implications of a parentage result test vary by state and according to whether the putative parents are unmarried or married. If a parentage test does not meet forensic standards for the state in question, a court-ordered test may be required for the results of the test to be admissible for legal purposes. For unmarried parents, if a parent is currently receiving child support or custody, but DNA testing later proves that the man is not the father, support automatically stops. However, in many states, this testing must be performed during a narrow window of time, if a voluntary acknowledgement of parentage form has already been signed by the putative father; otherwise, the results of the test may be disregarded by law, and in many cases, a man may be required to pay child support, though the child is biologically unrelated. In a few states, if the mother is receiving the support, then that alleged father has the right to file a lawsuit to get back any money that he lost from paying support. As of 2011, in most states, unwed parents confronted with a voluntary acknowledgement of parentage form are informed of the possibility and right to request a DNA paternity test. If testing is refused by the mother, the father may not be required to sign the birth certificate or the voluntary acknowledgement of parentage form for the child. For wedded putative parents, the husband of the mother is presumed to be the father of the child. But, in most states, this presumption can be overturned by the application of a forensic paternity test; in many states, the time for overturning this presumption may be limited to the first few years of the child's life.

Reverse paternity testing

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Reverse paternity determination is the ability to establish the biological father when the father of that person is not available. The test uses the STR alleles in mother and her child, other children and brothers of the alleged father, and deduction of genetic constitution of the father by the basis of genetic laws, all to create a rough amalgamation. This can compare the father's DNA when a direct sample of the father's DNA is unavailable. An episode of Solved shows this test being used to know if a blood sample matches with the victim of a kidnapping.

See also

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Genetic:

References

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[35]

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[36]

  1. ^ "A Non-invasive Test to Determine Paternity in Pregnancy" New England Journal of Medicine May 3, 2012
  2. ^ Pollack, Andrew (June 19, 2012). "Paternity Blood Tests That Work Early in a Pregnancy". The New York Times.
  3. ^ Presciuttini, Silvano; Toni, Chiara; Spinetti, Isabella; Rocchi, Anna; Domenici, Ranieri (April 2006). "An unusual case of disputed paternity: When the legitimate children of a deceased alleged father deny DNA". International Congress Series. 1288: 831–833. doi:10.1016/j.ics.2005.09.043.
  4. ^ Akinola, Adeyemi Adewale; Anana, Mariam (September 4, 2024). "Exploring Entrepreneurial English in Digital Information: Harmonizing News Headlines with their Introductions in Phoenix". Access: An International Journal of Nepal Library Association. 3: 51–64. doi:10.3126/access.v3i1.69420. ISSN 2822-2075.
  5. ^ Guo, Xin; Bayliss, Philip; Damewood, Marian; Varney, John; Ma, Emily; Vallecillo, Brett; Dhallan, Ravinder (2012). ""The New England Journal of Medicine "A Non-invasive Test to Determine Paternity in Pregnancy" May 3, 2012". New England Journal of Medicine. 366 (18). The New England Journal of Medicine: 1743–1745. doi:10.1056/NEJMc1113044. PMID 22551147.
  6. ^ Bloomfield, Frank (July 1, 2009). "The peri-conceptional origins of the life-long physiological consequences of being a twin". Physiology News (Summer 2009): 31–33. doi:10.36866/pn.75.31.
  7. ^ Butler, John (October 22, 2014). Advanced Topics in Forensic DNA Typing: Interpretation. Elsevier. pp. 349–400. ISBN 9780124052130.
  8. ^ Butler, John (2005). Forensic DNA Typing Biology, Technology, and Genetics of STR Markers. Elsevier. pp. 201–240. ISBN 0-12-147952-8.
  9. ^ Gjertson, David W.; Brenner, Charles H.; Baur, Max P.; Carracedo, Angel; Guidet, Francois; Luque, Juan A.; Lessig, Rüdiger; Mayr, Wolfgang R.; Pascali, Vince L.; Prinz, Mechthild; Schneider, Peter M.; Morling, Niels (2007). "ISFG: Recommendations on biostatistics in paternity testing". Forensic Science International: Genetics. 1 (3–4): 223–231. doi:10.1016/j.fsigen.2007.06.006. ISSN 1872-4973. PMID 19083766. S2CID 24450117.
  10. ^ "History of DNA Testing - DNA Diagnostics Center".
  11. ^ "History of DNA Testing - DNA Diagnostics Center".
  12. ^ "The Tuscaloosa News - Google News Archive Search". news.google.com.
  13. ^ a b Thuesen, Nikolas Hallberg; Klausen, Michael Schantz; Gopalakrishnan, Shyam; Trolle, Thomas; Renaud, Gabriel (November 8, 2022). "Benchmarking freely available HLA typing algorithms across varying genes, coverages and typing resolutions". Frontiers in Immunology. 13. doi:10.3389/fimmu.2022.987655. ISSN 1664-3224. PMC 9679531. PMID 36426357.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  14. ^ "Frequently Asked Questions About DNA Testing | Catholic Legal Immigration Network, Inc. (CLINIC)". www.cliniclegal.org. Retrieved March 24, 2025.
  15. ^ "Information for Parents on U.S. Citizenship and DNA Testing". travel.state.gov. Retrieved March 24, 2025.
  16. ^ "Brazilian identical twins both ordered to pay maintenance". April 2, 2019. Retrieved March 24, 2025.
  17. ^ "Court Ordered Paternity Tests - The Requirements of a Legal Paternity Test". September 8, 2021.
  18. ^ National Association of Testing Authorities, Accredited Facilities
  19. ^ "Paternity Test - CanadianDivorceLaws.com". www.canadiandivorcelaws.com.
  20. ^ "China's census gives rise to paternity test, distrust; netizens' comments and our thoughts - Ministry of Tofu 豆腐部". www.ministryoftofu.com. Archived from the original on November 20, 2012. Retrieved December 20, 2012.
  21. ^ Art. 16-10 of the Civil Code
  22. ^ Art. 226-25 to 226-30 of the Penal Code. These articles only ban non consensual testing and don't apply to testing by parents of minors.
  23. ^ "French men's insecurity over paternity of offspring creating 'a society of doubt'". The Irish Times.
  24. ^ "BIONEWS - Germany passes genetic test laws". www.bionews.org.uk. Archived from the original on June 20, 2013. Retrieved March 4, 2013.
  25. ^ "Alpha Biolabs - Paternity Test". November 19, 2010. Archived from the original on November 19, 2010.{{cite web}}: CS1 maint: bot: original URL status unknown (link)
  26. ^ "Constitutional Court Rules Secret Paternity Tests Still Illegal - Germany- News and in-depth reporting from Berlin and beyond - DW - 13.02.2007". DW.COM.
  27. ^ "Court Orders Paternity Test Despite 'Mamzer' Factor - Israel National News". Israel National News. December 21, 2007.
  28. ^ Sinai, Ruth (October 22, 2008). "Court May Side With Husband on Paternity Test". Haaretz.
  29. ^ Ilan, Shahar (July 24, 2008). "MKs Okay Paternity Testing". Haaretz.
  30. ^ "Fast, 100% Accurate AABB DNA Paternity Test - Philippines". dnahustisya.ph.
  31. ^ DNA Rules of Evidence: Philippines Archived 2014-01-20 at archive.today
  32. ^ "AFP: Paternity tests take off in Spain thanks to French ban". February 10, 2013. Archived from the original on February 10, 2013.
  33. ^ "Spain Offers Paternity Tests to Suspicious French Fathers". Medindia. November 28, 2007.
  34. ^ "Accredited Parentage Testing Facilities". February 18, 2006. Archived from the original on February 18, 2006.
  35. ^ Presciuttini, Silvano; Toni, Chiara; Spinetti, Isabella; Rocchi, Anna; Domenici, Ranieri (April 2006). "An unusual case of disputed paternity: When the legitimate children of a deceased alleged father deny DNA". International Congress Series. 1288: 831–833. doi:10.1016/j.ics.2005.09.043.
  36. ^ Akinola, Adeyemi Adewale; Anana, Mariam (September 4, 2024). "Exploring Entrepreneurial English in Digital Information: Harmonizing News Headlines with their Introductions in Phoenix". Access: An International Journal of Nepal Library Association. 3: 51–64. doi:10.3126/access.v3i1.69420. ISSN 2822-2075.
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