Across a wide range of studies, researchers often conclude that the home environment and children’s outcomes are causally linked. In contrast, behavioral genetic studies show that parents influence their children by providing them with both environment and genes, meaning the environment that parents provide should not be considered in the absence of genetic influences, because that can lead to erroneous conclusions on causation. This article seeks to provide behavioral scientists with a synopsis of numerous methods to estimate the direct effect of the environment, controlling for the potential of genetic confounding. Ideally, using genetically sensitive designs can fully disentangle this genetic confound, but these require specialized samples. In the near future, researchers will likely have access to measured DNA variants (summarized in a polygenic scores), which could serve as a partial genetic control, but that is currently not an option that is ideal or widely available. We also propose a work around for when genetically sensitive data are not readily available: the Familial Control Method. In this method, one measures the same trait in the parents as the child, and the parents’ trait is then used as a covariate (e.g., a genetic proxy). When these options are all not possible, we plead with our colleagues to clearly mention genetic confound as a limitation, and to be cautious with any environmental causal statements which could lead to unnecessary parent blaming.
Bibliographical noteFunding Information:
S.A.H. is supported by Eunice Kennedy Shriver National Institute of Child Health & Human Development Grants HD052120 and HD095193. Views expressed herein are those of the authors and have neither been reviewed nor approved by the granting agencies. E.vB. is supported by NWO VENI fellowship 451-15-017 (“Decoding the gene-environment interplay of reading ability”) and ZonMw grant 531003014 (“Genetics as a research tool: A natural experiment to elucidate the causal effects of social mobility on health”). She is a member of the Consortium on Individual Development (CID; NWO Gravitation grant 024.001.003) and of Research Institute LEARN!.
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