Changes In Children DNA

DNA Change In Children

Many children of liquedators that helped clean up the radiation have been shown to have various mutations. The most likely cause of this would be that they inherited some radiation from the parents, who received large amounts of radiation. These children are tested for these changes in DNA, the children's siblings who had been conceived before their parents' exposure served as internal controls, in addition to external controls from families who had not been exposed. There was a high count in DNA change, but we don't know if there are long teem effects of these DNA changes, but they have not been ruled out. But, as time went on, many of these changes Yet there armer many facts that put down this theory, including the amount of time in-between the exposure to radiation and the time of the conception. One of the ideas suggest that the cause of these mutations are of internal radiation. It shows a massive failure in the modelling of radiation risk by the International Commission on Radiological Protection. This is mostly from the atomic bomb that was dropped on Hiroshima, single massive bursts of gamma radiation delivered externally. But the ICRP studies are absolutely silent on the effects of internal radiation.
Questions:
1) Why are the children of liquedators(people the tried cleaning Chornobyl) having changes in their DNA?
2) How are they tested for DNA change? Or, to word it better, who is their DNA compared to?
3) What evidence is against this theory about DNA change?