Key issues in contemporary behavioral genetics

In this article I give a brief overview of the field of behavior genetics in past and present. I identify several areas of rapid advance, as well as some that are posing problems. The most serious issue currently in need to be addressed is the definition of phenotypes. All too often, certain behavioral constructs are assumed to be evaluated in behavioral tests, without either the test or the construct having been adequately validated. It is most likely that many of the conflicting results and failures to replicate reported in the literature can be traced back to this problem. Validation of behavioral constructs and the ways to test them is urgently needed in both animal and human behavioral and psychiatric genetics.