that by the age of 30 the average American would receive germ cell exposures as follows: 1, Batkground cr ratural radicactivity 4,3r 2, Medical x-rays 38 3, Fallout from weapons testing if ccnwo tinued at rate for the past 5 years O,lr (0,02 to 0,5r) They then estimated that tne exposure nesessary.-to- > double the mutations rats in humans lay beiween 520and 160r, ~—_ 4 ts more likely 30r ts 80Or, but alss tnat different gene isci were quite different in tneir sensitivity ts radiation, Taking these observaticns into consideratisn tney fais that if the population as a whole were to ressive ns more than lOr man-made exposure to radiation to ths germ z6lis pricr t5 ths age of thirty no serious consequences would result, They therefore, rescommended that no one should receive a total azzumulated dose to the reproduction cells of more than 50r pricr to th$ ege cf thirty without clear cut medical reasons, and that in any svent the average exposure of populations as a whole shculd not exesed ed 10r by the age of thirty, They point cut thet t at present about 1/3 this figure is already being used up by medizal x-rey exposures many of which could with proper presactizns be greatly redused, AS to cesupaticnal expesures the Committee considered this to be a limited group = ns estimates were made as to iis actual or potential size, As finalized in the repert the reccmmendatisns are: 1, There should be a national system of keeping radia-— tion exposures on all persons as is now practiced at AEC astablish- ments . NAS 2, Medisal expcsures to the germ cells should be reduced, 3, No mera than i0r by age thirty for the population as a whole, 4. The subject shouid be reviewed pericdically with a view to possible further redusticn in exposixs, 5. Ne body, however, employed, should recsive more than 50r of exposure pricr ts the age cf 30, 6, For special astivities é€ inherent in which are a greater liability to oversxpssuve individuals who for one reason or other are unlikely to prsoreate srculd be selected, ~ 2 ~ A ie Wns tae _ SCrENGES