The Article ‘Interplay between Law and Genetics’ by Poornashree P aims to elucidate that every individual’s behavioural traits are related to their genetics. The article contains the interconnection between law and genetics and in this technical era, it has become an inalienable issue of concern. Genetic variation is undoubtedly a reason for the increasing criminal offences. The author… Read More »

The Article ‘Interplay between Law and Genetics’ by Poornashree P aims to elucidate that every individual’s behavioural traits are related to their genetics. The article contains the interconnection between law and genetics and in this technical era, it has become an inalienable issue of concern. Genetic variation is undoubtedly a reason for the increasing criminal offences. The author discusses some of the relevant biological factors that create an ever-lasting impact on the mindset of an individual. Various research work has been discussed to make this topic vivid.

The Author highlighted one of the decisions of the European Court where the behavioural pattern was given significance while granting a penalty to the accused. Various Challenges which are faced in deciding criminal liability have been well-explained in this article. The author sums up the blame on the scientist because the author feels the area of research only focuses on the social aspect only. The author feels that the impact of the family is certainly maximum in rapidly developing crimes.

Introduction: Interplay between Law and Genetics

The collision of science and law is inevitable. The two varied fields of discipline challenge each other with contemporary problems that might as well create grey areas in their respective fields of study. The latest inventions and discoveries in the Science and Technical arena have often created perplexities in the framework of law and justice. One of such challenges includes the presence of genetic variants that are said to alter human behaviour, compromising the individual’s mental capacity, thus resulting in the causation of crime. In the present time, this has indeed opened up a new spectrum of novel and peculiar issues in the criminal justice system.

Rapid development of Behavioural Genetics

Behavioural genetics has gained significance and has witnessed rapid development in the recent past. The pattern of human behaviour can not only be analysed on the basis of the influence of one’s life experiences but also by studying the possible influence of one’s genetic predispositions. One study concluded that some ‘factor’ is transmitted by convicted parents to their offspring, increasing the likelihood that their children will also be convicted for criminal offences.

This ‘transmitted factor’ being biological implies that biological factors are involved in the aetiology of at least some criminal behaviour. Another study delineates that certain genetic variants (MAOA-Monoamine oxidase A) have an unmediated connection to an individual’s aggressive behaviour, thus acting as an influencing factor for committing a crime. The issue gained momentum in 2010 after a landmark Italian case, wherein the convict’s prison sentence was reduced, considering the presence of genetic variants in him that were thought to be associated with a predisposition to aggressiveness, violence, and impulsivity.

European Court: Historical Decision

The landmark Italian case is one of its kind in the history of European courts. It was the first case wherein behavioural genetics affected the sentence awarded to the criminal. The convict, who had a history of schizophrenia and other psychiatric illnesses, had his prison sentence reduced to 9 years and 2 months, around three years less than he would have received had he been deemed to be of sound mind.

In the appeal hearing, the defence lawyer presented a psychiatric report as evidence, after conducting a genetic test, that the defendant is a carrier of the MAOA gene which is said to have predisposed individuals to violent behaviour. On this footing, the judge further reduced a year of the prison sentence. The judge further added that the defendant’s genes

“would make him particularly aggressive in stressful situations.”

Various Challenges in assessing one’s criminal liability

Behavioural Genetics has posed various challenges in assessing one’s criminal liability. The mental state which must be proved against the accused is expressly specified in the definitions of various crimes. Rupert Cross and Philip Asterley Jones say that the expressions “malice aforethought”, “willfully”, and “knowingly” must be proved to establish mens rea. These expressions perceptibly reveal that the accused was well aware of the relevant circumstances and foresaw relevant consequences.

Even if the actus reus of the crime is charged, the accused is entitled to be acquitted if he is not also shown to have had the requisite knowledge of fact and foresight of consequences. An imbalanced biological system resulting in different behavioural aspects of the individual leads to difficulty attributing men’s rea. This, perhaps, comes under the ambit of the defence of insanity.

Important aspect of American Jurisprudence

The American jurisprudence incorporated the M’Naghten Rule, specifically the notion of not attributing guilt if the actor suffered from such a mental defect for the reason that he or she could not know the nature and quality of his or her behaviour during the commission of the act. Further, the American Criminal Justice System has repeatedly attempted to modify the rule to include advances in modern psychological sciences, specifically with the inclusion of the notion of the offender’s irresistible impulse.

Joseph A. Mitchell has pointed out that the empirical evidence that has been collected over the last decade seems to indicate that this is the area where social scientists should be researching if we are to find the truth regarding the causation and treatability of criminality. He further says

“Unfortunately, too many social scientists have been focusing on the ‘social’ rather than the ‘scientist’, choosing to exclude more prosaic explanations of human behaviour such as genetic predisposition, adaptation, natural selection, and natural biological functioning. Instead, most attempt to explain human behavioural causation through the means of psychosocial speculation and numerical approxima

tion models.”


Assessment of genetic variants is prone to misinterpretations. In the aforementioned Italian case, the issues revolving around the reduction of a prison sentence considering the presence of a gene that predisposes aggressiveness raise concerns. It is to be noted that scientists might have diversified opinions on the real predictive value and impact of these genetic variants.

Thus, the admission of susceptibility test reports in legal proceedings creates perplexity and ambiguity in the system. It is pertinent to note that genetic evaluation is purely research-based and does not possess clinical validity or utility.

Francesca Forenzo opines that no susceptibility test should as yet be used in forensic or other judicial settings. He adds that genetic tests in forensic contexts should be restricted to tests with proven clinical utility for the diagnosis of disease relevant to the case judged. This indeed compromises the legal principle of “Innocent until proven guilty” to “you’re guilty because you’ve got it”. This is, most evidently, incompatible with the basic principle of the Criminal Justice System.


[1] Feresin, Lighter sentence for murderer with ‘bad genes’, Available Here

[2] Cross and Jones, Introduction to criminal law, Available Here

[3] Joseph A. Mitchell, Biological Determinants of Mens Rea: When Choice Fails to Compensate for Biopsychological Perseveration, Available Here

[4] Francesca Forzano, Italian appeal court: a genetic predisposition to commit murder?, Available Here

[5] Pieri E & Levit M., It could just be an additional test, couldn’t it?” Genetic testing for susceptibility to aggression and violence, Available Here

Updated On 7 Aug 2022 4:54 AM GMT

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