Science Fiction and Shed DNA
[Editor's Note: This piece is a reply to Elizabeth E. Joh, Reclaiming "Abandoned" DNA: The Fourth Amendment and Genetic Privacy, 100 Nw. U. L. Rev. 857 (2006) (link).]
Introduction
The year is 2025. The population is 325 million, and the FBI has the DNA profiles of all of them. Unlike fingerprints, these profiles reveal vital medical information. This universal database arrived surreptitiously. First, the Department of Defense's repository of DNA samples from all military personnel, established to identify remains of soldiers missing in action, was given to the FBI. Then local police across the country shadowed individuals, collecting their shed DNA for the databank. On the way, thousands of innocent people were imprisoned because they had the misfortune to have race-based crime genes in their DNA samples. Sadly, it did not have to be this way. If only we had passed laws against collecting and using shed DNA . . . .
This science-fiction story is loosely inspired by an essay on Reclaiming "Abandoned" DNA, by Professor Elizabeth Joh. Her article makes "the case for special consideration of abandoned DNA" in view of the nature and "potential uses of this information."[1] Like Joh, I believe that collecting shed DNA deserves scrutiny, as does the prospect of a universal database.[2] Furthermore, I agree that DNA is a uniquely revealing form of trace evidence and that the legal system must recognize its power to expose an individual's genetic secrets. Nonetheless, we part company on the threat posed by collection of "abandoned DNA." First, the notion that abandoned DNA is a viable means for covertly building a population-wide database is implausible. Second, any claim that the DNA profiles currently used for identification constitute "predictive medical information" is false. Third, the prospect of preventive detention of bearers of "crime genes" lends little support to a warrant requirement. Fourth, the practice of collecting shed DNA has no particular relationship to theories of "race" as a biological reality.
In making these points, I take no position on whether shed DNA deserves Fourth Amendment or other protection. The scope of the Amendment will be addressed in a separate article that will show how some forms of "abandoned DNA"âor the chemical analyses of this moleculeâcan be brought within the Fourth Amendment. Here, I focus on what Joh calls "the implications of abandoned DNA" as a motivation for the legal reforms she advocates.

