Developmental science has not been immune to this revolution. In contrast to the field of ethology, which has a rich tradition of examining of the genetic underpinnings of innate animal behavior (i.e., instincts), the study of genetic influences on human behavior was originally limited to the fledgling field of behavior genetics, which met with great resistance for arguing that behaviors widely “known” to have environmental etiologies (e.g., schizophrenia was caused by bad parenting) were under genetic influence. But genetic influences were not measured in these early behavior genetic studies, rather, they were inferred using family, twin, and adoption designs, by testing for similarity across different types of relatives with different degrees of genetic and environmental overlap. This meant that to study genetic influences on behavior required special study designs and methodologies not widely employed by the broader psychological or developmental community. All this has changed now that it is possible to genotype specific genes and incorporate this information into any on-going study. This has made genetics accessible to mainstream developmental science. This molecular advance occurred in concert with growing recognition
