Document Type



Burton H. Brody Prize Paper (J. Balkin, C. Jolls, R. Siegel ) (best paper on constitutional privacy), and Margaret Gruter Prize Paper (R. Burt, R. Brooks, D. Kahan) (best paper on how ethology, biology, and related behavior sciences may deepen our understanding of law)


The FBI’s Combined DNA Index System (CODIS) and its component databases are expanding rapidly. Originally profiling only certain classes of convicted violent felons, CODIS now includes all federal arrestees, convicts, and foreign detainees, as well as convicts from every state and arrestees from many. This expansion is driven by the desire to solve more crimes with forensic DNA evidence, which has proven a potent investigative tool.

This expansion has largely been blessed by courts, although some question remains as to the ultimate Fourth Amendment treatment of including DNA from arrestees.

The most controversial expansion, however—and one not yet examined by any court—comes in the form of familial DNA searching, a technology that permits indirect identification of blood relatives through their genetic similarity to a profiled offender. FBI labs have rejected this “problem child” of CODIS, but in response to strong state lobbying, the Bureau now permits states to perform familial searches at will. Two states, California and Colorado, have authorized familial DNA search regimes.

Familial DNA search is worrisome for several reasons: It overextends CODIS both legally and technically, improperly subjects individuals to scrutiny solely on account of their relatives’ misdeeds, and greatly aggravates the racial inequality already present in the offender database.

This paper summarizes the scientific and legal underpinnings of U.S. forensic DNA databases, and argues for several key changes to database policy.

Section I presents scientific background sufficient to understand what DNA profiles are, what they are not, and how DNA identification functions. This section also explains the principles underlying familial DNA search, and discusses DNA profiling in terms of genetic privacy.

Date of Authorship for this Version