In modern conditions of constant population decline and the presence of adverse demographic processes in Ukraine, the urgent task is to identify the most significant genetic and demographic factors affecting the adaptation of the population, as well as monitoring changes in the volume and structure of the genetic load caused by congenital pathology. The frequency of congenital malformations of newborns in the Kherson region increased (from 22.3±5.4 % in 2000-2008 to 40.1 ± 8.2 % in 2009-2017). In recent years, there has been a statistically significant increase in the frequency of hereditary pathology of newborns among the rural population of the region (from 1.09 to 1.95 %).The total frequency of congenital malformations increased in almost all areas of the Kherson region (from 20.2±1.4, 27 to 27.6±1.3 %) and averaged 30.2±6.4 %. Significant differences in this indicator were found between some nations of the region. Malformations of the circulatory system (28.5 %), musculoskeletal system (26.05 %) and the genitourinary system (15.25 %) occupy a leading place in the structure of congenital pathology. The prevalence of congenital malformations is inversely correlated with the prevalence of spontaneous miscarriages (r =-0.52± ±0.12; tr=2.4> t05=2.12), which indicates the presence of a screening effect that eliminates non-viable genotypes in embryonic period of ontogenesis.Rural population where the share of interethnic marriages has increased over the years of research, is characterized by a higher prevalence of congenital malformations (r=0.50±0.46; t=2.3>t05=2.12). In population (with an endogamy index of 0.5 and higher), an increase or relative constancy of the proportion of homolocal mono-ethnic Ukrainian marriages and a lower prevalence of congenital malformations among newborns are observed. The level of endogamy does not significantly affect the prevalence of malformations (r=-0.20±0.24; tr=0.8