Recent evidence from psychological science and genetics suggests that genetic influences underlie all behavior as well as the most worrisome social inequalities. This may be considered to call into question traditional conceptions of agency and agent responsibility. They could be thought to be undermined if gene-environment transactions were sufficiently potent in influencing behaviors. Here we identify the theoretical parameters that require investigation and the conceptual challenges to agent responsibility that arise from research in behavior genetics. We (i) introduce the empirical (...) basis of the discussion, (ii) identify the particular questions that arise from considering the connection between behavior genetics and agent responsibility in the context of the legal system, (iii) bring into focus the general challenges to agent responsibility, and (iv) outline a potential resolution. (shrink)