Say you are a rich and famous man, and your DNA profile is known to schemers. I read that paternity tests are 99.99 percent accurate, which I interpret to mean that the proportion of people that would be flagged as your child purely by chance is 1-0.9999=0.0001, or 1 in 10000. What is the legal defense against schemers who keep testing until they find some people who are some of those 1 in 10000 matches? Does he need to prove he could never have possibly been in the same location as the mother? Or does she need to prove they were in the same location? Is same location (proven or not disproven) as mother and positive paternity test sufficient?
I think the current DNA tests are far more precise than that, to the point where unless the child is a close relative, the odds of a match are astronomical. I found one lab promising 99.9999% accuracy, so 1 in 1 million.
The 99.99% probably refers to the cheap home tests available, which simply answer the question - is he the dad, yes or no?
And if you believe someone is pulling a scam, there is more serious, in depth testing.
Ok, say these are hackers who go into a DNA database, so one in a million still gives a good pool of people. What is the defense strategy?
DNA Tests can only support a claim. If the test result comes back a match, but other circumstance make it impossible that the child was fathered by the celebrity, that would be enough to overcome the Test result.
How impossible? Who has the burden of proof? Beyond a shadow of a doubt or preponderence of the evidence or…? Who weighs the evidence?
The problem is that there are lot of possible things to test and a given lab will only test a subset of these.
So the schemer finds a match. The R&F’s lawyers order a 2nd test from somewhere else whose subset differs somewhat from the first one’s. A mismatch comes up. (And even if the schemer ran tests at more than one lab, there’s still more labs. Esp. ones that would do extra tests for a price.)
Then the R&F lawyers have a lot of Important Questions to ask the schemer and the supposed offspring that might result in negative consequences.
Right out of the gate, the travels of the rich and famous are usually pretty well documented. I might be a match for Prince Charles or Howard Hughes but they were probably nowhere near the same city as my mother that month. The younger the alleged child, the more likely travel documentation exists. If you limit the pool to people in the right place, your pool of 4 billion male suspects now becomes perhaps a million or less; and the odds that it’s someone like Joe the Plumber that matches, not one of your senators, gets better.
Also IIRC, there a re certain genetic markers that determine racial origins (which is how they determined overall human migration in prehistory). So you are not really starting with 4 billion random candidates, the selection is limited to mostly people of the same ethnic origin.
There was a case on the Paternity Court TV show where a young woman found a man said to be related to her on one of the DNA websites, who she thought might be her father. But the testimony established that although he had lived nearby, he had never met her mother, and the full DNA test showed he clearly was not her father.
Sounds like Bayesian probability would somehow enter into this. First thing would be to define “accuracy” as false positives and false negatives.
And if the scammers go to that many women to try to find one who will go along, sooner or later they’re going to find one who’s not going to go along, and who will report the scammers.
Need answer fast?
In my state, in a paternity suit, the moving party must prove at least one act of intercourse in addition to any other evidence, which usually includes DNA results. In theory, it is still possible to try a paternity suit to a jury–which I actually did, twice, circa 1996-1997. Most such cases are tried to a Judge these days.
For such a scheme to work, all the DNA would need to be submitted to the lab by one of the parties. In my experience, one party doesn’t submit the DNA to the lab. The putative father submits his separately (with the child’s, if he has custody) than the mother (with the child’s if she has custody). They aren’t submitted in one package. In addition, there must be some evidence that intercourse occurred between the two around the period of conception. (Nearly all cases this is not contested). If the person alleging paternity wanted to sue until she found a match, she’d go broke just in filing fees, let alone legal fees and lab fees.
Eta: What Oakminster said.
Maybe I’m missing the point but I don’t see how this would work.
The only way this scam would work is if the woman knew a man who was willing to impregnate her - and who had the same matching genes as the billionaire they plan on setting up.
How are they going to plan something like that? Just go ahead and have a baby and then hope the genes match? Remember the odds are somewhere between ten thousand to one to a million to one against there being a random match.
There are plenty of scams out there with much lower costs and much higher chances of success.
Remember, children get 23 chromosomes from each parent - one of each pair comes from each parent. A complete DNA test would also test the mother, to see if some of the “matching” chromosomes indeed did not come from the mother (Maybe her father was rich guy’s uncle, etc.) So you need a father who happens to have at least 23 chromosomes - one of each pair - that match the rich mark’s DNA, and then needs to give only those to the child. It’s like flipping a coin 23 times and always getting heads. 1:2^23 is like one in 10 million or so.
When it comes to paternity, you don’t get points for “close”. exactly one of each pair, for 23 pairs, must be an exact match for the alleged father - and the others must match the mother. Any partial match imply cousin, niece/nephew, grandchild, 3rd cousin, “I’m from West Virginia”, etc.
md2000, genetics doesn’t work that way. Shortly after conception there is a gene shuffle that occurs. So the kid will have chromosomes that contain genes from both parents. (Exceptions are the Y chromosome and maternal mtDNA.)
No, no, no. The DNA database hackers find a few hundred kids that would be flagged as his child by the DNA test. Then they investigate the mothers and befriend those they think she could argue she had sex with him, and would go in on the scam when finally proposed. Perhaps the idea could be brought up as a joke at first, so she won’t blow the whistle if disinclined.
That 99.99% (or 99.999%) accuracy figure relates to proof of paternity.
On the other hand, DNA testing that excludes someone as being the father is considered 100% accurate. From available info I gather that having several mismatches in DNA testing is proof positive (medically and legally) that someone is not the father.
Attempting a scam as described in the OP presumes that a precise match of DNA markers could be found (which seems far more unlikely than the initially quoted odds suggest) and plausibility of an encounter, otherwise the perpetrators are likely to wind up in jail for an extended period.
If I’m 18 and the test says a 22-year-old is my parent, that’s probably a glitch.
This could work if the scam target and the real father are identical twins I suppose, except for the fact that the scam would be blindingly obvious to everyone.