20 Growth and DevelopmentStudies a few instances showed conflict between there- In evaluating the growth and development data corded date and the available circumstantial evi- on these children, serious inconsistencies in birth date information have been uncovered. Official written birth records did not exist for most of the children. The parents actually had norealistic perspective of time. No local or regional events, tragic or otherwise, were rememberedtoserve as reference points. The births of some children had been registered at Majuro, but even among these Table 10 Skeletal Ages in 6-Year-Old Children Subject Age at No. Sex 2 3 5 6 65 M M M M F 54 955 962 980 996 814 M F F F F M 33 exposure, mo F Chronological age in 1959, yr Skeletal age* —in 1959, yr 16 17 16 16 15 6 6 6 6 6 2 %2 Aa H2 he 4 2 21%2 3 K2 5 %2 3 %2 12 ** ** ** ** ** 6 a 61% 6 a 6 Ke 6 H2 62 T t T 6'%2 t 5 2 20 6 2 7 Sie *Greulich-Pyle standards. dence. Since almostall analyses of growth data depend basically on the use of chronological ages, the painstaking task of improving the validity of the age data was undertaken. This amounted toa virtual reconstruction of the biological history of the childhood population of the island. Interviews were held with the parents, relatives, and village elders. Cross-examinations were conductedto obtain all relevant information. In spite of these efforts, a significant lack of accurate information remained in manycases. Further attempts to check birth dates are necessary before classification of the children into age groups can be done with reasonable validity. Anearlier analysis of the skeletal ages of the Marshallese children had indicated possible retardation in development among the exposed group.” Since such comparisonsrequired reference to accurate chronological ages, further detailed analyses of this type were deferred. It was noted, however, that in the 6-year chronological age group three boys andonegirl out of five boys and two girls exposed to radiation were markedlyretarded in skeletal maturation (Table 10). The birth dates of these particular children seemed firmly established. The boys showing mostretardation (#2,3,and 5) were 16 to 17 monthsold and the girl (#65) 15 monthsold at the time of expo- **Control. tNofilm. Table 12 Table lt Comparison of Stature (1958, 1959, and 1960) Height and Weight of 6-Year-Old Children Subject No. Weight, lb 2 108.3 41.5 99.3 32.0 ° 65 oes O84 PO 33.0 lose v ao h 112.5 47.5 33 54 955 962 102.2 115.8 , 10g ? 980 119.8 996 | 108.0 B14 Cry Skeletal age peers TS Height, Weight, cm Ib Height, cm 3 111.7 a re bu ig it 39.5 95.3 32.5 43.8 118.2 47.4 tb 3 _ 7 _ — _ 43.8 35.0 43.0 of Children With Retarded Osseous Development With That of Their Next Younger Sibs _ _ — _ Stature, cm Sex Born 1958 Subject (#5) M_ 10/20/52 95.7 Subject (#2) Sib (#91) M 10/23/52 103.0 108.3 115.6 M 1/3/55 89.8 97.1 104.1 Sib (#85) Subject (#3) M M Sib (#83) _ Sib (#86) =F — Subject (#6) M — Subject (#65) Sib (#84) M_ F M 9/ 7/54 9/11/52 6/8/54 95.5 1959 1960 98.8 102.2 100.9 108.0 985 102.2 106.7 97.6 986 113.0 10/17/54 90.6 97.0 103.5 10/14/52. 100.4 12/4/52 5/31/54 93.0 94.2 984 1029 106.3 111.8 98.6 104.8