Taking into account new approaches in medicine of the 21st century (personalization, prediction, prevention and participation), biogeochemical features of the Amur region, and inhomogeneity of ethnic makeup, the purpose of the work was to determine the occurrence frequency of genes of detoxification system predisposition (glutathione S-transferases – GST) among the population of the Amur region. Ethnic and environmental components were taken into account. Risk groups of pregnant women were formed. Substantiation of a personalized approach to a set of preventive measures for the development of pathological conditions was made. Evaluation of gene polymorphism of phase II xenobiotic biotransformation (GSTT1, GSTM1) was carried out by polymerase chain reaction using diagnostic kits produced by the Center of Molecular Genetics (Moscow). 255 pregnant women of newly-arrived and indigenous population from urban areas (Khabarovsk city) and rural areas of the Amur region (Nanai district) were examined. All examined women were divided into 3 groups: 1 group – urban newcomers, representatives of the (European) Slavic race (n=128); 2 group – rural newcomers, representatives of the (European) Slavic race (n=67); 3 group – rural indigenous of the Mongoloid race (the Nanais), who represent small-numbered peoples of the North, Siberia and the Far East of the Russian Federation from places of traditional residence (n=60). A comparative analysis of the obtained results was carried out in the observed groups. The results were also compared with the data provided by the authors of other regions of the Russian Federation similar in climatic and geographical characteristics (Eastern, Western and Northern Siberia). An ethnic feature of the detoxification system (GSTT1 and GSTM1) of the Amur region indigenous women (nanaian women) was revealed, which is a high frequency of combined deletion polymorphism. The study not only contributes to the scientific and theoretical knowledge, but it is also the basis for the development of additional methods of prevention and correction of disorders associated with exo- and endogenous influence on women in preconception and gestational periods.