DNA Forensics: Setting the (Fool’s) Gold Standard

“All That Glitters Isn’t Gold,” a recent article in the Hastings Center Report by UC Hastings Associate Professor of Law and Center for Genetics and Society senior fellow Osagie Obasogie and UC Berkeley sociologist Troy Duster, exposes the flawed scientific assumptions that underlie many modern DNA forensic techniques and policies.

As a jumping off point, the authors home in on a 2009 report from the National Research Council entitled Strengthening Forensic Science in the United States: A Path Forward [pdf]. The report notes widespread inconsistency in forensic policies, procedures and practices, and states that non-DNA forensic techniques should be held to the same standards of reliability as those of DNA evidence. 

While Obasogie and Duster commend the report as an “important first step,” they point out that all DNA forensic techniques are not equal in their accuracy. They argue that emerging techniques, especially those that involve matching samples (usually those found at crime scenes) with those stored in large DNA databases, require urgent scientific and legal scrutiny.

These methods, which include familial searches and “cold hits,” are less accurate and predictable than often assumed but, the authors point out, often inherit the “gold standard” reputation of the 13-loci match between two isolated DNA samples. This failed distinction has led to a disturbing upsurge of state policies that seek to expand criminal databases through mandatory DNA collection from non-convicted arrestees. 

Obasogie and Duster also importantly illustrate that a growing reliance on questionable database matching techniques has serious implications for racial justice. They note that the “dramatic overrepresentation” of minority groups in prisons and DNA databases “raise significant questions regarding systemic bias.” 

Examining broader social, legal and ethical issues raised by DNA forensics is becoming increasingly important. Obasogie and Duster’s work demonstrates that scientifically unfounded faith in all things DNA forensic is leading the justice system into dangerous territory.