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DNA as a Defense


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DNA as a Defense

            There are countless variables that influence human behavior. Genes are one factor that have been shown to influence the way people act, and some people believe that behavior can be almost completely explained by the genes that one inherits. Others believe that who a person is relies fully on how they were raised- where they grew up, who raised them, and their quality of life. This nature vs. nurture debate has appeared countless times in various situations, including in the courtroom. The question is, do genetics have any place in court cases when trying to explain why somebody committed a crime? Nicole Westman argues that genetics are an ineffective excuse to use to explain criminal behavior in her Popular Science article, “Your DNA Probably Didn’t Make You Do It.” 

     In her article, Westman describes how lawyers use certain genes to explain their client’s violence. She explains that the MAOA gene is connected to antisocial and criminal behavior in some cases, and even helped a convicted murderer receive a shorter sentence in 2009. However, the connection between the MAOA gene and criminal behavior is a very controversial topic, because a single gene is not going to make somebody commit a criminal act. She explains that other social and environmental factors play a huge role in criminal behavior. Lawyers use this defense because if they can convince the judge or the jury that their client was predisposed to violent behavior or law breaking, they can take some of the blame off their client and possibly receive a reduced sentence. Studies mentioned in this article also concluded that in most cases, the DNA defense does not persuade the judge or jury to give a lesser sentence. In fact, the jury may find the criminal more dangerous to society if there is a violent gene in their DNA. Lawyers have not backed down after these studies, because in desperate times there is still the very small chance that this argument will be successful. According to Westman, this argument is not likely to be used in everyday cases. It will have more of an impact in cases where the defendant is claiming to have commit the crime because of mental illness, and the genetics just add to that argument (Westman 1).

     One of Westman’s arguments against using genetics to explain criminal behavior in court is that the DNA defense does not persuade judges or juries to give a lesser sentence, so it is pointless to use. Nevertheless, lawyers have used these arguments since genetic testing began. In a National Geographic article, “My DNA Made Me Do It? How Behavioral Genetics Is Influencing the Justice System” by Virginia Hughes, she describes another example similar to the MAOA gene, called XXY Syndrome. This argument was used in the late 1960’s, when genetics were first being used in court, and claimed that the extra chromosome was connected to criminal behavior because of the prevalence of this syndrome in prisons. Similar to the MAOA gene today, judges and juries were not swayed by this information (Hughes 1).

     Westman does acknowledge the counterargument that genes have some sort of influence on behavior. She mentions a scholarly article by Appelbaum and Scurich that cites recent studies on the heritability of behaviors, including two large studies on behavior in twins. The results indicated that there was 37-57% heritability for aggressive behavior, and 67% heritability for antisocial behavior (92), presenting the “nature” part of the nature vs. nurture debate. This information was connected to the MAOA enzyme that effects neurotransmitters in the brain.

     Although there is evidence of the link between these genes and certain behaviors, Westman argues that it is not a cause-effect situation. She states that “MAOA’s criminal connection is controversial-it’s usually discussed carefully, with scientists clarifying that a gene alone is not going to make someone violent or amoral” (1). In “My DNA Made Me Do It? How Behavior Genetics is Influencing the Justice System,” Hughes points out that people look for explanations for why others do horrible things, and we often turn to science for that comfort. In 2012, Adam Lanza killed 20 children and 6 members of school staff at a Connecticut elementary school, also killing his mother and himself. Less than two weeks after that, the medical examiner had Lanza’s DNA screened for abnormalities (1). The point of his DNA being screened was to find a scientific reason for his actions, an abnormality in his DNA that causes aggression or violence. Nevertheless, searching for these reasons was futile because behavior is so incredibly complex and there are so many contributing factors, the answer to why he committed the awful crime cannot be found in his genetics. This supports Westman’s argument that DNA is not going to make someone commit a crime, that people just look for scientific reasons to explain human behavior.

     Furthermore, Westman argues the “nurture” part of this debate. She discusses that there are other influences on behavior, not just a person’s genetic code, “Social and environmental factors also play a role; not everyone with a particular genetic mutation will commit a crime; and not every criminal has a particular gene mutation.” (Westman 1). Somebody may be predisposed to certain behaviors with particular genes, but environmental components are also extremely important. There is a large amount of evidence to back up her argument, including in the cited studies in “Impact of Behavioral Genetic Evidence on the Adjudication of Criminal Behavior.” When someone has the MAOA gene and also experienced childhood maltreatment, they are far more likely to exhibit violent or criminal behavior (Appelbaum and Scurich 92). Michael Shader lists many of the environmental and social influences that can lead to criminal behavior in “Risk Factors for Delinquency: An Overview.” Some of these risks include exposure to violent television, low IQ, low socioeconomic status/poverty, antisocial parents, poor relationship with parents, antisocial peers, poor school performance, and numerous other factors (Shader 4). Obviously, her argument that there are outside factors other than genes that influence behavior, specifically criminal behavior, is supported by multiple studies.

     Westman argues that it is futile to use DNA as an excuse for criminal behavior in court. She explains that judges and juries are not influenced by genetic evidence in court, and that it may even hurt the defendant’s case. She mentions the counterargument that genetics have a substantial influence on how someone behaves, but brings up the well-known idea that environment and society play a large role in people becoming criminals. Westman provides a convincing argument and solid evidence that there are countless components that make up human behavior, so criminal actions cannot be defined by possessing a single gene.

    

Works Cited

Appelbaum, Paul S., and Nicholas Scurich. “Impact of Behavioral Genetic Evidence on the Adjudication of Criminal Behavior.” The journal of the American Academy of Psychiatry and the Law 42.1 (2014): 91–100.

Hughes, Virginia. “My DNA Made Me Do It? How Behavioral Genetics Is Influencing the Justice System.” National Geographic. 4 June 2014. http://phenomena.nationalgeographic.com/2014/06/04/my-dna-made-me-do-it-how-behavioral-genetics-is-influencing-the-justice-system/

Shader, Michael. “Risk Factors for Delinquency: An Overview.” U.S. Department of Justice. 2001. https://www.ncjrs.gov/pdffiles1/ojjdp/frd030127.pdf

Westman, Nicole. “Your DNA probably didn’t make you do it.” Popular Science. 19 September, 2017. https://www.popsci.com/genetic-behavior-evidence-court

 

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