What Real-World Criminal Cases Tell Us About Genetics Evidence

Abstract

This Article, which is part of a symposium on "Law and Ethics at the Frontier of Genetic Technology," examines an unprecedented experimental study published in Science. The Science study indicated that psychopathic criminal offenders were more likely to receive lighter sentences if a judge was aware of genetic and neurobiological explanations for the offender’s psychopathy. This Article contends that the study’s conclusions derive from substantial flaws in the study’s design and methodology. The hypothetical case upon which the study is based captures just one narrow and unrepresentative component of how genetic and neurobiological information operates, and the study suffers from serious omissions that affect the validity and reliability of its results. It is important to call attention to these problems given that the study’s widely-publicized findings are likely to bolster inaccurate perceptions regarding the dangers of allowing behavioral genetics evidence in criminal cases. This Article concludes with a detailed discussion of a number of recent criminal cases involving behavioral genetics evidence. Familiarity with such cases may improve the real-world applicability of future experimental studies exploring the influence of genetics evidence on criminal cases.

Keywords: genetics, behavioral genetics, psychopathy, crime, criminality, punishment, judges, judicial decision-making, trials, biology, race, environment, experimental design, death penalty