Considerable attention is paid to the role of consanguineous marriage as a causative factor in the prevalence of genetic disorders. At the same time, the potential influence of community endogamy on overall levels of homozygosity and disease profiles remains largely under-investigated. With the ongoing global epidemiological transition from infectious to non-communicable disease, the impact of genetic disorders will become increasingly important and a thorough understanding of the determinants of human population-genetic structure will be all the more necessary. In particular, the genetic components of adult-onset diseases will become more obvious and assume greater significance. Similarly, refinements of study design to incorporate intercommunity genetic variation appear to be an essential prerequisite in pharmacogenetic research if the concept of individualized treatments is to achieve reality, with equivalent subject-control comparison difficulties also predicted in forensic genetics.