Kim Cooper, Assistant Professor in the Cell and Developmental Biology Section of the UC San Diego Division of Biological Sciences, discusses the advantages and the potential risks of CRISPR/Cas9-based active genetic systems and ways to maximize benefits to society. How do we decide when not to do the things that we can? In the last couple of years, a new "active genetic" technology has been shown to promote efficient inheritance of desired gene modifications in insects. We have now shown that we can do this in rodents. This allows the assembly of complex genotypes that were once unthinkable due to cost, time, and more. Such applications could improve drug testing and mouse models of complex human genetic diseases. These same approaches could also be used to control invasive wild rodent populations and vectors of disease. Despite these benefits, many have raised concerns about unintended consequences of the release of transgenic organisms. (#33672)