46 and 7 years after the accident were about the same for exposed and unexposed persons of comparable age.~° FERTILITY, MISCARRIAGES, STILLBIRTHS, AND GENETIC EFFECTS Effects on fertility were not apparent as judged by comparison of birth rates for the exposed and unexposed populations. During the first 4 years after exposure an increase in miscarriages and stillbirths was noted in the exposed women, 41% of the births (13 in 32 births) in this group terminating in nonviable offspring compared with 21% (8 in 38 births) in the unexposed women.Since that time, the incidence has been about the same in the two groups. One cannotbe certain thatthis effect is actually due to radiation exposure because of the small number of women involved. No specific genetic studies have been carried out, but differences in incidences of abnormalities was complicated by physical and psychic trauma and by malnutrition factors not operative in the case of the Marshallese children. The 175-rad gamma dose would seem to be too small to cause any direct effect on bone growth, and the esti- mated dose to the bones from internally absorbed isotopes probably can also be disregarded since this source contributed only about 3 to 4 rads over a 10-year period. Bone growth studies in weanling rats given sublethal exposures have shown an indirect effect on subsequent growth of shielded legs, but this appears to be based largely on a radiation- induced lowered food consumption.** [t is of inter- est that 25 of 31 exposed children were noted to lose several pounds of weight during the Arst 6 to 8 weeks following exposure. However, the influence of change in environmentin producing this effect cannotbe ruled out. in children of exposed compared with those of un- DEVELOPMENT OF THYROID NOOULES erally negative results of large-scale genetic studies Thyroid nodules were removed from 3 teen-age exposed girls after the 10-year survey. Most pathologists consulted did not feel that radiation exposed women have not been observed. The gen- on the offspring of exposed Japanese” indicated that detailed studies on the Marshallese would not be fruitful. GROWTH AND DEVELOPMENT STUDIES Comparison ofexposed with unexposed children of the same ages indicated slight retardation effects in the exposed males. The boys exposed at ages | to 5 showed retardation of statural growth as well as bone age. This was most marked in those ex- posed at 15 to 18 months of age. The average skeletal maturation in the exposed boys was about 7 months behind that of their unexposed peers. Though weight gain also appeared slightly retarded in this group, it was not statistically significant. The exposed girls showed nosignificant differences compared with unexposed giris. The slight retardation of growth in the male children who were exposed when <5 years of age as compared with unexposed males of the same age suggests that radiation may be a causal factor although possible mechanisms are not clear. The dose to bones from internally absorbed isotopes is believed to have been too small to have affected bone growth. Adverse effects on growth and devel- opment of Japanese children exposed to the atomic bomb have been reported by Greulich.” Reynolds,** and Nehemias.** However, the evalu- ation of such effects in these Japanese children could be implicated as the etiologic agent on the basis of the pathological findings alone, though some considered the findings typical ofthe lesions seen in children treated medically with radioactive iodine. However, the evidence is strong that the thyroid nodules in the Marshallese girls were in- duced by radiation. Correlation of the thyroid nodules with radiation exposure was substantiated by statistical analysis which showed thedifference in thyroid nodule incidence between the exposed and the unexposed children to be significantat the 1% level.* Moreover, Sheline et al.°* and Lindsav et al.** have reported the developmentof thyroid nodules 5 to 11 years after treatment of children with radioiodine for thyrotoxicosis. Dr. Lindsay reported that the sections of the glands removed from the Marshallese girls were similar to the glands of children who had been given I['* therapy. On the basis of a calculated dose of = 150 rads‘ to the adult thyroids from isotopes of iodine, it was estimated that the smaller thyroid glands of the girls exposed at 3 to 4 years of age received a total dose of the order of 1000 rads** (probable *Mr. Keith Thompson of Brookhaven National Laboratory carried out the x° test. “*Mr. Ralph fames and Dr. John Gofman. Lawrence Radiauon Laboratory, Livermore. California, re-examined the early data and recaiculated the thyroid doses.