§ 54. Dr. Summerskillasked the Prime Minister whether he is aware that the United Nations Scientific Committee emphasised that there is at present no known threshold of radiation exposure below which genetic damage does not occur; and if he will make a statement on the genetic effects of atomic radiation.
§ The Prime MinisterAs the House knows, radiation results from three sources: first, from natural sources, secondly, from medical or industrial applications, and thirdly, from nuclear tests. The ratios between these three in the United Kingdom are roughly 100, 22 and something between 1 and 2. The 63W genetic effect of the first type has been permanent since man existed; that of the second dates from the use of X-rays, etc.; the third is much more recent. There is no known threshold below which damage, however slight, may not occur, although research is being actively carried out on this matter. It is, however, evident that, even if all forms of manmade radiation were eliminated—and this includes of course all X-ray and similar medical applications—it would still not be possible to remove the even larger proportion of natural radiation to which the human race must be liable. At any rate, so far there has been no direct evidence of any genetic effects on man from very low rates of radiation.
The character of the problem makes research difficult since it is not easy to get results except from short-lived forms of life such as the fruit-fly. Mice are also now being used for this purpose.
If I might hazard a suggestion it may be that the human race has, in this case as with other pressures to which it is liable, been able by its recuperative powers to establish an equilibrium with the mutants.