# Non-Paternity aka Cuckoldry: Pre-DNA

**URL:** <https://boards.straightdope.com/t/non-paternity-aka-cuckoldry-pre-dna/424656>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [October 31, 2007, 1:50am UTC](https://boards.straightdope.com/t/non-paternity-aka-cuckoldry-pre-dna/424656 "2007-10-31T01:50:39Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![triolamj](https://avatars.discourse-cdn.com/v4/letter/t/e19b73/32.png) [@triolamj](https://boards.straightdope.com/u/triolamj)\
**Post date:** [October 31, 2007, 1:50am UTC](https://boards.straightdope.com/t/non-paternity-aka-cuckoldry-pre-dna/424656/1 "2007-10-31T01:50:39Z")

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I remember a newspaper article on non-paternity that was an outgrowth of a study laying the groundwork for DNA testing. Two researchers in southern Florida looked at the birth records of children born at a local hospital or hospitals which included the child’s and their parents’ blood types. Just comparing the blood types, the researchers were able to identify cases of non-paternity: an A+ mom and a B+ dad can’t produce a O- baby. The researchers projected a non-paternity rate of 5%-8% with the suspicion that with the greater precision of DNA testing that it could climb to 10%.

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**Author:** ![Sublight](https://avatars.discourse-cdn.com/v4/letter/s/439d5e/32.png) [@Sublight](https://boards.straightdope.com/u/Sublight)\
**Post date:** [October 31, 2007, 2:09am UTC](https://boards.straightdope.com/t/non-paternity-aka-cuckoldry-pre-dna/424656/2 "2007-10-31T02:09:47Z")

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Good timing. Cecil’s most recent column was on just this subject.

[Who’s your Daddy? Is it true 10-15% of children in modern society were not sired by their putative fathers?](http://www.straightdope.com/columns/071019.html)

Long story short, several reports (pre- and post-DNA testing) made the papers claiming 10-30 percent non-paternity, but these were all pretty shaky. A couple of more rigorous studies (using DNA testing), on the other hand, estimate the actual rate among the general population is under 5%.

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**Author:** ![MLS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MLS](https://boards.straightdope.com/u/MLS)\
**Post date:** [October 31, 2007, 5:04pm UTC](https://boards.straightdope.com/t/non-paternity-aka-cuckoldry-pre-dna/424656/3 "2007-10-31T17:04:13Z")

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[QUOTE=triolamj]  
I remember a newspaper article on non-paternity that was an outgrowth of a study laying the groundwork for DNA testing. Two researchers in southern Florida looked at the birth records of children born at a local hospital or hospitals which included the child’s and their parents’ blood types. Just comparing the blood types, the researchers were able to identify cases of non-paternity: an A+ mom and a B+ dad can’t produce a O- baby. The researchers projected a non-paternity rate of 5%-8% with the suspicion that with the greater precision of DNA testing that it could climb to 10%.  
[/QUOTE]

Actually, they could. The ‘O’ gene is recessive. The A+ mom could have a genotype of one gene for A, one for O. And one gene for + and one for -. The dad could have a similar genotype of BO and ±. Statistically, 1/4 of their kids will be AB, 1/4 AO, 1/4 AB and 1/4 OO. The latter will produce a pheonotype of type O blood. Similar pattern for Rh factor, except that since the Rh- gene is recessive, only 1/4 of their children will actually have the Rh- phenotype.