Future work is needed to replicate our findings. In many domains of research, replication can be a problem and concern has also been raised with regard to in Gene × Environment research (e.g., Duncan & Keller, 2011). Without replication, the critique remains that a particular study may be unduly influenced by factors unrelated to what is being studied and thereby produce artifactual results. To bolster confidence in our results, we created bootstrapped 95% confidence intervals, which offer insight into reliability of the moderated paths through multiple sample draws. Random sample splits are considered a particularly strong replication method because of homogeneity of samples, measurement, and methods (e.g. Johnston, Lahey, & Matthys, 2013). In addition, our findings add to a growing literature replicating DRD4 7−/7+ environmental moderation (e.g., Bakermans-Kranenberg & van IJzendoorn, 2011), and most of these studies indicate 7+ carriers are relatively more sensitive to environmental positivity, as we have shown in this study (see Pluess & Belsky, 2013). Finally, our findings also are largely consistent with the theories they tested. Thus, although independent sample replication is desirable, our analytic
