The cross-twin, cross-trait correlations were larger for MZ than DZ twins (Δχ2 (1) = 23.83, p < .001), indicating the influence of genetic factors on the stability of antisocial behavior. Further, the stability of antisocial behavior was greater for males than females, as evidenced by the larger within-twin, cross-trait correlations for males compared to females (Δχ2 (1) = 61.45, p < .001). There was also evidence that the magnitude of the genetic and environmental influences on the stability of antisocial behavior differed across sex, as the cross-twin, cross-trait correlations were larger for males than females (Δχ2 (1) = 34.41, p < .001). The cross-twin, cross-trait correlations were smaller for opposite-sex compared to same-sex DZ twins (Δχ2 (1) = 4.92, p < .05), indicating a qualitative sex difference in the sources of the stability of antisocial behavior.
