Medical Genetics. [15 to 25 % has been determined from blood tests of parents and offspring in Canada and the US.]"
From The Age 2000-03-26: "About 3000 paternity tests are carried out a year in Australia. In about 20 per cent of cases the purported father is found to be unrelated to the child. This figure is estimated to be 10 per cent in the general community".
From The REPORT Newsmagazine 2000-04-24: "The rate of wrongful paternity in "stable monogamous marriages," according to the Max Planck Institute in Munich, Germany, ranges from one in 10 with the first child to one in four with the fourth".
From the Independent 2000-05-12: "... biologists Robin Baker and Mark Bellis ... review of paternity studies also suggested frequent infidelity, with extra-pair paternity running between 1.4 per cent and 30 per cent in different communities".
From The Globe and Mail 2000-05-20: "Anecdotal evidence suggests these numbers bear out in Canada as well…. Maxxam Analytics in Guelph, Ont., performs approximately two paternity tests a day. And according to Dr. Wayne Murray, head of the human DNA department, one out of four men who come in pointing a finger at their spouse is not the biological father of the child in question".
From the Sunday Times 2000-06-11: "More than 250,000 tests a year are now conducted in America, and about 15,000 in Britain.... roughly 30% of men taking the tests discover that they are not the fathers of the children they regarded as their own. In the wider community, social scientists say up to 1 in 20 children are not the offspring of the man who believes himself to be their father".
From the Observer 2000-09-03: "One study followed couples waiting for NHS fertility treatment, where the men were 'azoospermic', meaning they produced no sperm and were totally infertile. The researchers found that 25 per cent of the women became pregnant before fertility treatment started".
From the American Association of Blood Banks - 2001-02-26: "The overall exclusion rate for 1999 was 28.2% for accredited labs. Exclusion rates for non-accredited US and foreign labs were slightly less at 22.7% and 20.6% respectively".
20% of men who think they are fathers are not.
Random DNA checks prove that 20% of men who think they are father are not.
This statistic is truly shocking.
There's a whole evolutionary game theory worked out to explain this.
Simply put, a woman wants to bind a man into a monogamous relationship so he provides food and resources for her and her children, while she maximizes the genetic diversity of her children by having them with several different men.
DNA test at childbirth should be required to determine the actual paternity.
Discussion from pregnancy message board:
It took me 2 years to get pg, we finally said screw it, stopped trying, and went to Mexico. Whammo, a vacation and margi's did the trick.
Your son looks kind-of Mexican, right?
shhhh- don't tell my husband
From the Guardian, 1998-07-14: "More than 25 years ago the consultant obstetrician E E Phillipp reported to a symposium on embryo transfer that blood tests on between 200 and 300 women in a town in the south-east of England revealed that 30 per cent of their children could not have been fathered by the men whose blood groups had also been sampled".
From the Dallas Morning News 1999-10-31: "DNA Diagnostics Center … an industry leader, says 30 percent of the men it tests prove to be misidentified. Similar numbers come from the Texas attorney general's office, which enforces child support: About a quarter of the men who disputed paternity in the last year turned out to be right. In Florida, the proportion was one-third".
From the Sunday Times 2000-01-23: "David Hartshorne, spokesman for Cellmark, said that in about