Bad nature, bad nurture, and testimony regarding MAOA and SLC6A4 genotyping at murder trials

J Forensic Sci. 2007 Nov;52(6):1362-71. doi: 10.1111/j.1556-4029.2007.00562.x. Epub 2007 Oct 17.


Recent research-in which subjects were studied longitudinally from childhood until adulthood-has started to clarify how a child's environment and genetic makeup interact to create a violent adolescent or adult. For example, male subjects who were born with a particular allele of the monoamine oxidase A gene and also were maltreated as children had a much greater likelihood of manifesting violent antisocial behavior as adolescents and adults. Also, individuals who were born with particular alleles of the serotonin transporter gene and also experienced multiple stressful life events were more likely to manifest serious depression and suicidality. This research raises the question of whether testimony regarding a defendant's genotype, exposure to child maltreatment, and experience of unusual stress is appropriate to present during the guilt or penalty phases of criminal trials, especially when capital punishment is a consideration. The authors present their experience in genotyping criminal defendants and presenting genetic information at criminal trials.

Publication types

  • Legal Case

MeSH terms

  • Adolescent
  • Adult
  • Expert Testimony
  • Forensic Genetics / legislation & jurisprudence*
  • Forensic Psychiatry / legislation & jurisprudence*
  • Genetic Testing / legislation & jurisprudence
  • Genotype
  • Humans
  • Male
  • Middle Aged
  • Monoamine Oxidase / genetics*
  • Polymerase Chain Reaction
  • Serotonin Plasma Membrane Transport Proteins / genetics*
  • Stress, Psychological / complications
  • Violence*


  • SLC6A4 protein, human
  • Serotonin Plasma Membrane Transport Proteins
  • Monoamine Oxidase