The psychopathic personality can be conceptualized as three interrelated dimensions, (a) an interpersonal style of glibness, grandiosity, and manipulation; (b) an affective disposition of callousness, lack of empathy, and unemotionality; and (c) a behavioral/lifestyle dimension of impulsivity, need for stimulation, and irresponsibility, underpinning a higher order construct, psychopathic personality. The authors used a self-report questionnaire (The Youth Psychopathic Traits Inventory) to study the importance of genetic and environmental influences on psychopathic personality traits in a sample of 1,090 monozygotic and dizygotic twin pairs, aged 16–17 years. Results showed a strong genetic influence behind the higher order “psychopathic personality” factor, underpinned by the three psychopathic personality dimensions. Over and above the effects to the higher order factor, significant unique genetic influences were also found in the callous/unemotional and in the impulsive/irresponsible dimension, but not in the grandiose/manipulative dimension. The authors propose that this latent psychopathic personality factor is a meaningful target for future etiological research.