Genetic databases are now helping elucidate gene function, estimate the prevalence of genes in populations, differentiate among subtypes of diseases, trace how genes may predispose to or protect against illnesses, and improve medical intervention. They achieve this by bringing together several streams of data about individuals: molecular genetic data; high quality standardised clinical data; data on health, lifestyle, and environment; and in some cases, genealogical data. The main strategy with genetic databases is to search, often by statistical brute force, for correlations, then use the genetic focusing to guide mechanistic, pharmaceutical, and other investigations. Searching for causal associations between genetic and health phenomena is not new. While marvelling at our glossy new human genome posters we mustn't forget the huge contributions to research, care, and counselling—and genome mapping—that continue to be made by many data collections on the classic mendelian disorders. What is revolutionary is the precision with which genetic makeup can now be known, at reasonable cost and speed, and the discrimination with which genetic details can be correlated, via computer, with other complex information. 1 2 Thus pharmacogeneticists are probing databases for gene related variabilities …