Parental testing
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A '''maternity or paternity identification test''' is conducted to establish whether a person is the biological [[parent]] of another person. A test to prove paternity (whether a man is someone's [[father]]) is known as a '''paternity test'''; a test to prove maternity (whether a woman is someone's [[mother]]) is called a '''maternity test.'''
Although paternity tests are more common than maternity tests, there may be circumstances in which the biological mother of the child is unclear. Examples include cases of an [[adopted]] child attempting to reunify with his or her biological mother, potential [[babies switched at birth | hospital mix-ups]], and [[in vitro fertilization]] where the laboratory may have implanted an unrelated embryo inside the mother.
Other factors such as new laws regarding reproductive technologies using donated eggs and sperm and surrogate mothers can mean that the female giving birth is not necessarily the legal mother of the child. For example, in Canada, the federal Human Assisted Reproduction Act provides for the use of hired surrogate mothers. The legal mother of the child may, in fact, be the egg donor. Similar laws are in place in the United Kingdom and Australia.
Although not constituting completely reliable evidence, several [[List_of_Mendelian_traits_in_humans|congenital traits]] such as attached [[earlobe]]s, the [[widow's peak]], or the [[cleft chin]], may serve as tentative indicators of (non-)parenthood as they are readily observable and inherited via [[Dominance relationship|autosomal-dominant]] genes.
A more reliable way to ascertain parenthood is via DNA analysis (known as [[genetic fingerprinting]] of individuals), although older methods have included [[blood type|ABO blood group typing]], analysis of various other [[protein]]s and [[enzyme]]s, or using [[HLA]] [[antigen]]s. The current techniques for paternity testing are using [[polymerase chain reaction]] (PCR) and [[restriction fragment length polymorphism]] (RFLP). For the most part however, DNA has all but taken over all the other forms of testing. Genetic testing has a 99.999% accuracy rate, or 99,999 out of 100,000 for the case where DNA samples of mother, child and the two disputed fathers are available.<ref>[http://www.dnareplication.info/paternitytesting.php "DNA Paternity Testing" George Kakaris, Biologist MSc in Applied Genetics and Biotechnology]</ref>
==DNA testing==
{{main|DNA testing}}
The [[DNA]] of an individual is almost exactly the same in each and every somatic (non reproductive) [[cell (biology)|cell]]. [[Sexual reproduction]] brings the DNA of both parents together randomly to create a unique combination of genetic material in a new cell, so the genetic material of an individual is derived from the genetic material of both their parents in roughly equal amounts. This genetic material is known as the nuclear [[genome]] of the individual, because it is found in the [[Cell nucleus|nucleus]].
Comparing the DNA sequence of an individual to that of another individual can show if one of them was derived from the other or not. Specific sequences are usually looked at to see if they were copied verbatim from one of the individual's genome to the other. If that was the case, then this proves that the genetic material of one individual could have been derived from that of the other (i.e.: one is the parent of the other).
Besides the nuclear DNA in the nucleus, the [[mitochondria]] in the cells also have their own genetic material termed the [[mitochondrial genome]]. Mitochondrial DNA comes only from the mother, without any shuffling.
Proving a relationship based on comparison of the [[mitochondrial genome]] is much easier than that based on the nuclear genome. However, testing the mitochondrial genome can only prove if two individuals are related by [[common descent]] through maternal lines only from a common ancestor and is thus of limited value (for instance, it could not be used to test for paternity).
In testing the paternity of a male child, comparison of the [[Y chromosome]] can be used since it is passed directly from father to son.
=== Non-invasive Prenatal paternity testing ===
Scientific tests can now determine paternity at 13 weeks into a pregnancy using non-invasive testing methods in many cases. This involves a simple blood sample taken from the pregnant woman's arm. The pregnant female's blood carries the fetus' DNA which can be compared to the DNA of the alleged father.<ref>[http://www.canadiancrc.com/NON-INVASIVE_Prenatal_DNA_Paternity_Testing.aspx "NON-Invasive DNA Paternity Testing in Canada" Canadian Children's Rights Council]</ref>
== Legal issues ==
In the [[United Kingdom|UK]], there were no restrictions on paternity tests until the [[Human Tissue Act]] 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 analyzing 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 [[Department for Constitutional Affairs]] accredits bodies which can conduct this testing. The [[Department of Health (United Kingdom)|Department of Health]] is also in the process of updating its voluntary code of practice on genetic paternity testing.
== Disproving paternity by use of blood types ==
A comparison of the blood type of both alleged parents and the child can disprove paternity in some cases. Only certain blood type combinations are possible and a mismatch may prove that the alleged biological father is, in fact, not the father of the child. See the [http://www.canadiancrc.com/Paternity_determination_blood_type.aspx Parent/Child Blood Type Comparison Chart] on the website of the Canadian Children's Rights Council.
==See also==
*[[David Blunkett paternity case]]
*[[Jefferson DNA data]]
*[[Paternity fraud]]
*[[DNA testing]]
*[[Dannielynn Birkhead paternity case]] (Anna Nicole Smith's daughter)
*[[Mosaic (genetics)|Mosaicism]], a genetic condition which can result in false results on DNA-based tests
==References==
<references/>
==External links==
* [http://www.hta.gov.uk/_db/_documents/2006-07-04_Approved_by_Parliament_-_Code_of_Practice_1_-_Consent.pdf]: The HTA's code of practice on Consent
* [http://www.canadiancrc.com/Paternity_Fraud.aspx Canadian Children's Rights Council - Child Identity Rights and Paternity Fraud]
[[Category:Applied genetics]]
[[Category:Family law]]
[[Category:Parenting]]
[[Category:Paternity|Testing]]
[[de:Abstammungsgutachten]]
[[es:Prueba de paternidad]]
[[fr:Test de paternité]]
[[it:Test di paternità]]
[[he:בדיקת הורות]]
[[nl:Vaderschapsonderzoek]]
[[fi:Isyystutkimus]]
[[uk:Тест на батьківство]]
[[zh:亲子鉴定]]