Getting Scholarship Into Court Project

Deborah Denno in NACDL's Champion Magazine, March 01, 2013

Media Source (PDF)

Deborah W. Denno
Courts’ Increasing Consideration of Behavioral Genetics Evidence in Criminal Cases: Results of a Longitudinal Study
2011 Michigan State Law Review 967–1047, SSRN:,cfm?abstract_id=2065523

This article analyzes a unique study of all criminal cases that addressed behavioral genetics evidence during a 17-year period (1994–2011), with a particular emphasis on the last four years of that time frame. The article shows that such evidence is now more widely used in court than ever before, it is introduced nearly exclusively by defense attorneys, and it is being accepted by judges for a wider variety of mental and behavioral disorders. Strikingly, this study found no case during 2007–2011 in which behavioral genetics factors were introduced by the state, much less employed as aggravating evidence or as indications that a defendant would be a future danger to others. These results indicate that such information can be advantageous for practitioners and courts in various ways. While such evidence appears to have been applied almost entirely for mitigation purposes in death penalty cases, the same objectives and outcomes fueling such usage can extend to other kinds of cases and circumstances. For example, behavioral genetics evidence can provide proof and diagnosis of a defendant's mental disease or defect in the context of an insanity defense or of other conditions and behaviors associated with many different kinds of defenses. In sum, this study shows that behavioral genetics factors can become an effective litigation tool along with a range of other kinds of variables and that courts are increasingly accepting of such evidence.