The goal of the current study was to evaluate whether and how parent–child conflict moderated the etiology of child CP. Results offered strong support for the presence of shared environmental moderation of CP by parent–child conflict: C did not significantly contribute to CP in those with low levels of parent–child conflict, but increased dramatically and significantly with increasing levels of parent–child conflict. A and E contributions to CP, by contrast, were unchanged across all levels of parent–child conflict. Despite their absolute etiological stability, however, the relative proportion of variance accounted for by A and E changed significantly across high and low levels of parent–child conflict, such that A and E were proportionally more influential at low versus high levels of parent–child conflict. These results fully persisted to observer ratings of the parent–child relationship, as well as to other operationalizations of child CP, to individual informant reports of conflict, and to the mother–child and father–child relationships. Such findings thus serve to not only illuminate the origins of child CP, but also provide important empirical support for the bioecological model of G × E.
