why are there still effect of the Hiroshima and Nagasaki bombing up to today? What causes those abnormalities in people

Question: why are there still effect of the Hiroshima and Nagasaki bombing up to today? What causes those abnormalities in people today who their forefathers were affected?
- Keywords:
  Hiroshima,
  nagasaki
Asked by Joan G to Peter, Jonathan, Grace, Doris, David, Ann on 30 May 2019.
- Grace Kago answered on 30 May 2019:
  
  These two bombings used nuclear warfare, so there was quite a bit of radiation that was released to the environs of these bombings. Exposure to radiation might result in mutations/aberration to DNA, and since DNA is hereditary, this might be why current descendants are affected.

Question: why are there still effect of the Hiroshima and Nagasaki bombing up to today? What causes those abnormalities in people today who their forefathers were affected?