Subject No. Age Sex Frag- Dicen- ments trics Rings Exch- No. of Chromosome No. of Celis with anges Aberrations Aberrations Chromatid Breaks Isogaps Remarks* Exposed, 70 rad (continued) 70 25 #F 81 18 =#6OF 84 9 M i 1 2 1 1 1 1 2 2 2 2 Exposed in utero Child of exposed 9F1 Unexposed 105 5 F 1 830 25 M 1 859 71 =F 1 1 1 931 10 M } 1 1 938 25 *F 1 1 1 982 43°F 1 1 1005 31 M 3 3 3 1 1043 29 «=F 3 3 2 2 * Except for Subject Nos. 3 and 64, all thyroid pathology was adenomatous goiter. Case 64 had a mixed papillary and follicular carcinoma of the thyroid, 1 3 Case 3 is a hypothyroid child.