Genetic Evidence: The Unwilled Crime

Abstract

To avoid criminal liability, some defendants claimed to have committed offences as a result of a genetic predisposition to violence, aggression and other behavioural traits, as if they were compelled to act, rather than by free will. It is not sufficient to state that genetics played a causal role in explaining the criminal behavior. Such genetic claim must be backed up by convincing expert evidence in proof of same. The research examined the introduction of certain genetic deficiencies (XYY syndromes, Huntington disease, Monoamine Oxidase A deficiency and other syndromes) in criminal trials under various jurisdictions. The methodology is doctrinal with primary and secondary sources on Law, Bioethics and Genetics textbooks, journals, judicial authorities and online materials. The research found that genetic evidence is increasingly relied upon at criminal trials, particularly in the developed countries, notwithstanding the courts’ skepticism towards same. Despite the lack of express provisions in support of a genetic defence under the Nigerian Criminal Justice System, however certain provisions have been found to accommodate a genetic claim. The research recommended majorly the need for the criminal justice system to welcome new ideas from disciplines involved in genetics and related fields. There is also a need for the establishment of special health and rehabilitative institutions for persons with these genetic make-ups.