A limitation of this study is that childhood antisocial behavior was assessed retrospectively. Henry, Moffitt, Caspi, Langley, and Silva (1994) found that when participants were asked to retrospectively report on delinquent acts, participants tended to both under- and over-report these acts. However, Henry et al. noted that participants may have been quite accurate in recalling whether or not they had engaged in a delinquent act - they just did not accurately recall the age when they began to engage in the behavior. Thus, retrospective recall may not have unduly biased reports of CD in our study, as participants were not asked to report precise dates for their antisocial acts. Nonetheless, it is possible that there is a genetic component to retrospective recall, which could have resulted in over-estimates of the heritability of CD. However, as Jacobson et al. (2002) noted, if retrospective recall is genetically influenced, then the heritability of antisocial behavior might be expected to increase as the length of the recall time increases. This pattern was not observed in our study, as the heritability of antisocial behavior was
