<P> In the rare cases of survival for individuals who were in utero at the time of the bombing and yet who still were close enough to be exposed to less than or equal to 0.57 Gy, no difference in their cognitive abilities was found, suggesting a threshold dose for pregnancies below which, no life - limiting issues arise . In 50 or so children who survived the gestational process and were exposed to more than this dose, putting them within about 1000 meters from the hypocenter, Microcephaly was observed, this is the only elevated birth defect issue observed in the Hibakusha, occurring in approximately 50 in - utero individuals who were situated less than 1000 meters from the bombings . </P> <P> For those who did not suffer ARS, or who survived it . In a strictly dependent manner dependent on their distance from the hypocenter, in the 1987 Life Span Study, conducted by the Radiation Effects Research Foundation, a statistical excess of 507 cancers, of undefined lethality, were observed in 79,972 hibakusha who had still been living between 1958 - 1987 and who took part in the study . </P> <P> An epidemiology study by the RERF estimates that from 1950 to 2000, 46% of leukemia deaths and 11% of solid cancers, of unspecificed lethality, could be due to radiation from the bombs, with the statistical excess being estimated at 200 leukemia deaths and 1,700 solid cancers of undeclared lethality . </P> <Ul> <Li> Effects of nuclear explosions on human health </Li> <Li> Radiation poisoning </Li> </Ul>

How many survivors of hiroshima and nagasaki are still alive