Data were analyzed from the Cambridge Study in Delinquent Development to examine the reciprocal effects between family risk and involvement in an antisocial lifestyle. Results revealed that the measure of family risk did not have an appreciable effect on determining which boys would become embedded in an antisocial lifestyle. Importantly, the lack of an association between family risk and an antisocial lifestyle was observed not only in the longitudinal models but also in cross-sectional analyses that modeled reciprocal effects. When reciprocal effects between the family and the boy were modeled, the results revealed that boys’ involvement in an antisocial lifestyle significantly increased the risk level of the family. The analysis of the Cambridge Study in Delinquent Development data provides support in favor of a child-effects explanation for the relationship between family risk and an antisocial lifestyle. A contentious debate has been waged over the effects that parents and the family have on the development of children. One line of research reveals that experiences that occur within the household are the driving force for why children turn out the way that they do. Other findings indicate that the relationship between family experiences and different child outcomes is much more complex. Advocates of this position maintain that any association between parenting measures and child outcomes is spurious and can be partially accounted for by “child effects”. Data came from the Cambridge Study in Delinquent Development, which is a prospective longitudinal study of 411 boys residing in working-class areas of London. Figures, appendix, and references