The Probability of Hereditary Defects Resulting in Offspring from Ovarian Irradiations

Abstract

The quantitative results of the biodynamic effects of roentgen rays on the germinal cells of plants and animals cannot be transferred to man, because (1) the results depend on the structure of the gonads, the process of maturation of the germinal cells, the structure and the number of the chromosomes, and the like, and hence vary with the variety, subspecies, species, and race: (2) the irradiation dose in human therapy is different from that used in experimentation: (3) in man, the results arise from the absence of inbreeding, and (4) man has a long generation span and few descendants, while plants and animals have a much shorter generation span and many descendants. The dangers with respect to children that result from delayed fertilization, in case, by chance, fecundation of women temporarily sterilized occurs, are under these circumstances so slight that they do not need to be considered. In order to prove this, the most favorable assumptions possible are proposed, namely, monofactorial fixation of the hereditary characters, exclusively morphologic mutations and no lethal factors, all injuries affecting the sum total of characters of a high degree, an undiminished fertility of the women treated—not less than that of the average woman—normal fitness to mate and normal fertility of the descendants, and a frequency of temporary sterilization in excess of what actually occurs. Let us assume that in Vienna, with a population of 1,800,000 (about 1,000,000 women), one hundred women are temporarily sterilized each year: then in the second generation of women, among 100,000 individuals 0.0295 person at the most might be damaged as to hereditary characters; that is to say, one child in 3,380,169. If the mortality of the children, of the juveniles, and of the persons of productive age of the first generation of women were equal to 0 and all these persons were to be mated, there would be, on the basis of the present birth rate, 188 years required to bring the second generation of women up to 3,380,169 persons. But, in view of the present fertility and the present population of Vienna, a still greater number of years would be required in order to attain that number from the second generation of women. In reality, the prospect is very slight that a single child among the 3.4 million children descended from the second generation of women would be damaged in its development by roentgen rays previously applied to its remote ancestor in the female line. Discussion H. Adler, M.D.: It was difficult for me, a gynecologist, to follow the speakers in their detailed accounts of research on hereditary transmission and their presentation from the standpoint of higher mathematics, although Dr. Borak expounded the whole problem very finely and clearly.