Re: Dna testing on a child and the % of results between brothers being the dad.

Melissa,

I recently answered a question very similiar to yours on this site. I am not a gentic counselor or a doctor so do not use my anwer for legal matters. Paternity typing is similiar to the DNA analysis that we do in crime labs. But the full answer depends on the type of DNA analysis that is done. Crime labs use STR, mDNA and Y-STR analysis while paternity labs may still do DQa and PM. And paternity labs do give statistics as to the probability of soemone being the father if it's a match - the higher the number the better. Typical results are 99.9% probablity an individual is the father. 93% is rather low which means that the genetic locations used to determine the probability are fairly common. On top of this, a potential candidate for fatherhood is the brother. Obviously, brothers will have more in common and share more genetic information that two unrelated individuals. Based on all of this, I would recommend that both brothers have DNA profiling done to determine who the father is.

Regards,

Dale L. Laux
Forensic Scientist

[Moderator's Note: Dale has answered questions that are very similar to this one in 2003, 2006, and again last month. -- Steve Mack]