that by the age of 30 the average Amerizan would receive germ cell exposures as follows: 1, Background cr ratural radicactivity 4.3r 2. Medical x-rays 3 or 3, Fallout om weapons testing if ccn- tinued at rete for the past 5 years O,ir (0,02 to O,5r) They then estimated that tne exposure nesessary—to---- ae double the mutations rats in humans lay becween 52-and 150r, more likely 30r ts 8Or, but aiss that different gene isci were quite different in their aensivivity ts radiation, Taking these observaticns inte corsideraticn tney fait that if the population as a whole were to recsive no more than lOr man-made exposure to radiation to the germ 2elis pri:r ts the age of thirty no serisus consequences would result, They therefore, rescmmended that no one should reseive a toval azsumalated dose to the reproduction ecalis of more than 50r pricr to the ege cf thirty without clear cut medical reasons, and tnat in any event the average exposure of populations as a whole eshcild not excsed 10r by the age of thirty, They point cut thet at present about 1/3 this figure is already being used up by medizal x-ray exposures many cf which could with proper prsétautisns be grsetly reduced, A3 to ocsupaticnal expesires the Committee considered this to be a limited grtup = uo estimates were made as to it actual or potential size, As finalized in the report the reccmmendatisns are: 1, There should be a national system of keeping radia- tion exposures on all perscns as is now practiced at AEC establish- ments, NAS 2, 3, as a whole, Msdisal expesures to the germ cells should be reduced, No more than i0r by age thirty for the population 4. The subject shouid be reviewed pericdically with a view to possible further redusticn in exposurs, ~ 5. Ne body, however, emplsyed, should receive more than 50r of exposure pricr ts tne age of 30, 6, For special astivities inherent in which are a greater liability to cversxpcssre individuals who for con® reason or other are unlikely to prscreate srculd be selected, = A,SyECTIONS y THE i. SQHENCES