As is true for any research, it is important to place the current results in perspective. First, low LR is only one of many phenotypes related to the risk for heavy drinking and alcohol problems, and is the focus of the current analyses because low LR was established as a risk phenotype in the SDPS more than 40 years ago and the prospective nature of our work has kept that phenotype as our central measure of risk in both generations. Second, the data were gathered from a single research group using male probands and the prospective nature the SDPS required that we focus on a narrowly defined population that is mostly of EA ethnicity in San Diego, and therefore, the generalizability of the current results to other populations needs to be established. This is especially true for race where the high rates of EA participants in the SDPS made it difficult to evaluate how results might differ across racial or ethnic subgroups. Third, care must be taken in comparing male proband results with those from the combined group of male
