-~2absorbed from the fallout was not realized at that time, particularly in the children, and so thyroid effects were not anticipated even in the Rongelap group. In retrospect this is not surprising since only relatively re- cently has the degree of sensitivity of the thyroid, particularly in children, for the development of radiation-induced tumors begun to be appreciated. It is likely that the United States populations with thyroid exposures have not been as carefully followed as the Utirik population. Control groups: In 1954 an unexposed group of the Marshallese people living at Majuro was first chosen as a control group, but this group proved unsatisfactory and in 1958 a control population of some of the unexposed Rongelap people was established. These people were relatives of the exposed group and con- sisted of 150-200 people. This group is considered quite adequate as a con- trol group for both Rongelap and Utirik people. The slight difrerences in ethnic background between the two populations did not constitute reasons for having separate control groups. Children of exposed parents: The children of the exposed islanders have not been included on the regular examination list. This has not been considered necessary since studies of considerably larger groups of children of exposed paresnts in Japan have not revealed any clear-cut genetic effects and it was therefore felt that such studies on the Marshallese children were not indicated. Thoush the children have not been included for regular examinations they are examined and treater Stew Call ed, during the visits of our doctors to Utirik and Rongelap. , The lack of in- clusion of children of exposed on our examination list has been the cause of considerable unrest among the exposed people. the ERDA stand on this issue, (on te~h) Enclosures 1 and 2 present