Recent advances in the genetics of AD and other late-life dementias have provided new insights but also have raised new queries and ethical issues. This review reflects the current state of knowledge in a rapidly evolving field. The complex relation of genes and environment to AD, VaD, and other late-life dementias suggests that the answers to these many issues will evolve through time. New issues undoubtedly will arise as additional genes are discovered and new data accrue that relate APOE and other genes to the mechanism and expression of dementing illness. The clinical relevance and applicability of such research findings will increase when effective treatments become available. Given this potential, we encourage readers to monitor new developments as they arise.