Non-paternity event

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Non-paternity event (NPE) is a term in genetic genealogy and clinical genetics to describe instances in which the biological father of a child is someone other than who it is presumed to be. The presumption may be either on the part of the presumed father or by the physician. Non-paternity may result from a number of different scenarios: it may arise from sperm donation or when the mother had sexual intercourse with a man other than the presumed father. Other than the situations of gestational surrogacy and chimerism, the identity of a child's mother is seldom in doubt.[1] Non-paternity (and non-maternity) may also result from hidden adoptions: that is, when a child is never told he or she was adopted. Where there is uncertainty, then the only definitive diagnosis of non-paternity is from DNA testing.

The discovery of previously unsuspected or undisclosed non-paternity may have both social and medical consequences. Non-paternity that is due to a previously undisclosed extra-marital relationship often has serious consequences for a marital relationship. Non-paternity is medically relevant when interpreting the results and utility of genetic screening for hereditary illnesses.

Genetic genealogy[edit]

In genetic genealogy the term NPE is often used in a wider context to indicate a break in the link between the Y-chromosome and the surname. Such a breakage may occur because of formal or informal adoption, illegitimacy inside ("extramarital event"/infidelity or rape) or outside of marriage, child known by other surname (mother's maiden name, stepfather's name), the use of an alias or a deliberate change of surname.[2]

Testing for non-paternity[edit]

Further information: Parental testing

The only definitive test for paternity is DNA testing. Requirements for consent and counselling for DNA testing vary by country. Sons can be tested by Y-DNA and atDNA, daughters by atDNA and X-DNA.

Rates of non-paternity[edit]

Rates of non-paternity in single births[edit]

The rate of non-paternity is commonly quoted to be around 10%.[1][3][4]

However, a 2005 scientific review of international published studies of paternal discrepancy found a range in incidence from 0.8% to 30% (median 3.7%), suggesting that the widely quoted figure of 10% of non-paternal events is an overestimate. In situations where disputed parentage was the reason for the paternity testing, there were higher levels; an incidence of 17% to 33% (median of 26.9%). Most at risk of parental discrepancy were those born to younger parents, to unmarried couples and those of lower socio-economic status, or from certain cultural groups.[5]

A 2006 study examined non-paternity rates from 67 published studies. Non-paternity rates for men who were judged to have high paternity confidence ranged from 1.9% in the U.S. and Canada, 1.6% in Europe, and 2.9% elsewhere. In contrast, men in studies of disputed paternity, considered to have low paternity confidence, the rates of non-paternity were higher – 29% in the U.S. and Canada, 29% in Europe, and 30% elsewhere.[6]

The rates value varies according to the population studied:

  • United Kingdom:
    • 1 to 2% in a sample of 1,678 men[7]
    • 1.3%[8]
  • Mexico: 9.8% to 13.8% in a sample of 396 children[9]
  • Switzerland: 0.3 to 1.3% in a sample of 1,607 children[10]
  • United States:
    • A study in Michigan of 1417 white and 523 black children found non-paternity rates of 1.4% and 10.1% respectively.[11]
    • A study of 1748 Hawaiian families with 2839 children reported a non-paternity rate of 2 to 3%.[12]
  • France: 2.8% in a sample of 362 children[13]

Rates of non-paternity in one child of a pair of twins[edit]

Non-paternity of one child in a pair of twins, known as "heteropaternal superfecundation", is caused by the fertilization of one woman's eggs by the sperm from two separate fathers.

  • One study has found that even in twins, non-paternity of one of the twins (heteropaternal superfecundation) "occurs in around 2.4% of tested twins", or approximately 1 pair of twins out of every 42 pairs of twins tested.[1]

In one legal case in 2015, ruled on by New Jersey Superior Court Judge Sohail Mohammed, it was found that the twins at the centre of a paternity suit had been fathered by two different men. As a result of the genetic findings in that case, the male plaintiff who had been challenging the paternity of both twins, was ordered to pay support for just one of the twins.[2]

See also[edit]

References[edit]

  1. ^ a b Macintyre S & Sooman A (1991). "Non-paternity and prenatal genetic screening". Lancet 338 (8771): 869–871. doi:10.1016/0140-6736(91)91513-T. PMID 1681226. 
  2. ^ Georgia K. Bopp, Non-Paternal Event (NPE), Dec. 2006, URL Aug. 2012: http://freepages.genealogy.rootsweb.ancestry.com/~gkbopp/DNA/falsepaternal.htm
  3. ^ Neale MC; Neale BM; Sullivan PF (2002). "Nonpaternity in Linkage Studies of Extremely Discordant Sib Pairs". Am J Hum Genet 70 (2): 526–529. doi:10.1086/338687. PMC 384925. PMID 11745068. 
  4. ^ Rincon P (11 February 2009). "Study debunks illegitimacy 'myth'". BBC News. Retrieved 11 February 2009. 
  5. ^ Bellis MA; Hughes K; Hughes S; Ashton JR (September 2005). "Measuring paternal discrepancy and its public health consequences". J Epidemiol Community Health 59 (9): 749–54. doi:10.1136/jech.2005.036517. PMC 1733152. PMID 16100312. 
  6. ^ Anderson, K. G. (2006) Evidence from Worldwide Nonpaternity Rates. Current Anthropology, 47, 3 pp. 513-520. http://www.journals.uchicago.edu/doi/abs/10.1086/504167
  7. ^ King TE & Jobling MA (2009). "Founders, Drift, and Infidelity: The Relationship between Y Chromosome Diversity and Patrilineal Surnames". Mol Biol Evol 26 (5): 1093–102. doi:10.1093/molbev/msp022. PMC 2668828. PMID 19204044. 
  8. ^ Sykes, Bryan; Irven, Catherine (2000). "Surnames and the Y Chromosome". The American Journal of Human Genetics 66 (4): 1417–1419. doi:10.1086/302850. PMC 1288207. PMID 10739766. 
  9. ^ Cerda-Flores RM; Barton SA; Marty-Gonzalez LF; Rivas F; Chakraborty R (1999). "Estimation of nonpaternity in the Mexican population of Nuevo Leon: A validation study with blood group markers". Am J Physical Anthropol 109 (3): 281–293. doi:10.1002/(SICI)1096-8644(199907)109:3<281::AID-AJPA1>3.0.CO;2-3. PMID 10407460. 
  10. ^ Sasse G; Müller H; Chakraborty R; Ott J (1994). "Estimating the frequency of nonpaternity in Switzerland". Hum Hered 44 (6): 337–43. doi:10.1159/000154241. PMID 7860087. 
  11. ^ Schacht LE; Gershowitz H (1963). "Frequency of extra-marital children as determined by blood groups". In Gedda L. Proceedings of the Second International Congress on Human Genetics (Rome, Sept 6–12, 1961). Rome: G Mendel. pp. 894–97. 
  12. ^ Ashton GC (1980). "Mismatches in genetic markers in a large family study". Am J Hum Genet 32 (4): 601–13. PMC 1686125. PMID 6930820. 
  13. ^ Le Roux, Marie-Gaelle; Pascal, Olivier; Andre, Marie-Therese; Herbert, Odile; David, Albert; Moisan, Jean-Paul (1992). "Non-paternity and genetic counselling". The Lancet 340 (8819): 607. doi:10.1016/0140-6736(92)92139-7. 

External links[edit]