Can a DNA test actually tell with 100% certainty who the parent of a child is?

[Rabrrrrrr]

I was watching something on DVR, and it ended, and the TV show that happened to be on was Maury Povich's, and he came back with a DNA test to determine that some dude was, in fact, the father of some chick's kid.

And I wondered - are those tests absolute, or is it just a really high probability that a person is or is not a parent? If a test showed that this dude was the father, would a DNA test on that guy's brother also give a high positive?

If you know, please explain it all here!

[MissMillie]

1. I think the certainty level on those tests is 98% or better

that's what they usually say.

[DS1]

2. Hard to tell

All Springer show guests have samples which simply come back as 'substandard'

:shrug:

[Rabrrrrrr]

3. "Not only are you not the father, you're not even human!"

:rofl:

[sir_captain]

4. No test

can inherently have 100% specificity. Usually when checking paternity, common genetic alleles are compared. That said, in a practical sense, the test is pretty foolproof. The odds of some random person sharing more of your gene structure than one of your parents is pretty astronomical.

To answer your specific question, the father's profile would match his child's to a far greater degree than his brother's (parents share 50% of DNA as opposed to 25% for an uncle.)

[AllegroRondo]

5. Its never 100%

but they can get up to the 99%+ certainty. And for a court to legally declare someone a father and order child support, I believe it has to only be higher than 98% (at least in my state)

[supernova]

6. They usually phrase it as

"there is a 9__% probability that any to invidiuals are related. It's kind of a percentile rating.

Of all the people out there, 98% these two individuals are related to each other and not someone else (as closely).

[Iggo]

7. It is my understanding...

...that the only thing a paternity test can tell with 100% certainty is if you are NOT the father.

[triguy46]

8. This company says >99%

http://www.dnatesting.com/resource/paternityFaq.php