Genetic consequences of radioactive fall-outs of the Chelyabinsk plant producing plutonium (1949-1952) and the Chernobyl accident have been analysed. Three powerful radioactive fall-outs caused a population genetic dose of 682,801 cSv per 217,750 persons (the average dose was 2.25 cSv). Individual variations were from 1-2 mSv to 1.2 Sv or more. The population genetic dose from the Chernobyl accident was higher (32 x 10(6) man/cSv), but the individual dose was lower (mainly no more than 1 cSv). Progenic analyses of residents of radiation contaminated areas showed no increase in the incidence of congenital anomalies, spontaneous abortions, developmental microanomalies, and Down syndromes (except Byelorussia). Calculations of genetic consequences for the Ural region demonstrated that only in the most contaminated area (the average gonadal dose was 19.5 cSv); a 4.13% increase of the spontaneous level could be observed. In all other areas it was less than 1%. It is difficult to reveal possible genetic consequences of the Chernobyl accident using the real sample size of the newborns. Even in the areas with fall-outs above 15 Ci/km2, the incidence of congenital anomalies did not exceed 1% of the spontaneous level.
