Week 14 Genetics at Trial

One of the most controversial ways that behavior genetic research is being applied in the modern era is in the prediction of and determination of responsibility for criminal behavior. A court of law is an example of different, yet still concrete, goals - the defense wants to get the lightest sentence or a “not guilty” finding, while the prosecution typically seeks the most severe sentence available. The two sides are necessarily working with the same facts, yet are motivated to interpret them very differently.


  • Understand the recent history of the uses of behavior genetics research in legal settings.
  • Consider various societal and ethical implications of different interpretations of the same scientific information.

Participation Activities

  • Read & Discuss via Perusall: Berryessa Martinez-Martin & Allyse 2013 Ethical, legal and social issues surrounding research on genetic contributions to anti-social behavior. https://doi.org/10.1016/j.avb.2013.07.011
  • Read & Discuss via Perusall: McSwiggan Elger & Appelbaum 2017 The forensic use of behavioral genetics in criminal proceedings- Case ofthe MAOA-L genotype. https://doi.org/10.1016/j.ijlp.2016.09.005
  • Post an argument to the Legal Reasoning Discussion Forum
    • Imagine you are a legal researcher in the case of Tennessee v Waldroup (2010) (which was also discussed in the Week 2 Class Chat/Lecture on MAOA; recording available in Moodle).
    • You may choose to be a member of the PROSECUTION or the DEFENSE. (If you don’t have a preference, flip a coin: heads is Prosecution, tails is Defense. If you don’t have a physical coin, type “flip a coin” into google.)
    • Then, choose one of three options to post or respond to in-character:
      • For your chosen side (PROSECUTION or DEFENSE), respond to one of the two available prompts below (threads started by Jaime), OR
      • Head over to one of the prompt threads for the OTHER side and RESPOND to one post there, staying in-character as a researcher for the opposing side, OR
      • Respond to one instance of the OTHER side responding to YOUR side (e.g. if you’re the defense, post a response to a prosecutor responding to an original defense-side post).
  • Journal Response: Aggression GWAS press release
    • Write and post a short press release for an imaginary future study on the genetics of aggression, addressing how such information could or should be used in a legal setting.
    • Imagine it is the future and you have just completed the largest ever study of the genetics of aggression* (either a twin-heritability study or a GWAS, your choice).
    • Write a short (no more than 500 words) press release for your paper. It should include information on the method (a brief, layperson-friendly description), your sample (as large and with whatever demographic characteristics you would like), your phenotype operationalization (how did you define ‘aggression’?), and the primary results. All of this information will be completely made up, but must conform to what we would expect given the themes that emerge across phenotypes (e.g. everything is somewhat but not completely heritable, many genes of small effect, etc.).
    • At the end, briefly (in 2-3 sentences) address how this information could, and whether it should, be used in the context of the criminal justice system. That is, if you were to be called as an “expert witness” in a murder trial (such as Tennessee v Waldroup (2010), which was also discussed in the Week 2 Class Chat/Lecture on MAOA; recording available in Moodle) on the basis of your just-published-imaginary-paper and expertise in the genetics of aggression, what would you say?
    • Imaginary paper citation: Your-Last-Name, et al. (2025). The genetics of aggression. The Journal of Imaginary Studies, 1(1), 1-10.

Course Project Assignment Due

  • Project Milestone 6: Final popular source