The accused was charged with sexual assaults on two young male children.
At trial, he sought to introduce expert psychiatric evidence, including penile plethysmograph test results, to show he lacked the distinctive personality traits of someone who would commit such offences.
The trial judge excluded the evidence, finding it did not meet the Mohan criteria for admissibility, and convicted the accused.
The Court of Appeal allowed the appeal and ordered a new trial.
The Supreme Court of Canada allowed the Crown's appeal and restored the conviction, holding that the trial judge properly exercised his gatekeeper function in excluding the novel scientific evidence due to its lack of reliability and failure to establish a standard profile for the distinctive group of offenders.
