Atomic Bomb Genetics

Jay Fuster
March 11, 2016

Submitted as coursework for PH241, Stanford University, Winter 2016


Fig. 1: Aftermath of the atomic bombing in Hiroshima. (Source: Wikimedia Commons)

On August 6, 1945, the world witnessed one of the worst and most fatal attacks when an American bomber plane dropped an atomic bomb over Hiroshima, Japan. As seen in Fig. 1, the bomb left Hiroshima in ruins. This was the first time that an atomic bomb had ever been deployed, and within seconds 80,000 people were killed, and 90 percent of the Hiroshima was completely wiped out. The US then decided to deploy yet another atomic bomb on Nagasaki only three days later that killed roughly 40,000 people. Within a week of the second attack, Emperor Hirohito of Japan surrendered, essentially ending World War II. In his surrender speech, the Emperor cited the atomic bomb as "a new and most cruel bomb."

The effects of the atomic bomb explosion were not only immediately felt by those killed, but also the lasting radiation drastically altered the lives of countless more. Survivor's exposure to ionizing radiation in Japan arguably led to a greater risk of cancer, retardation, and birth defects. While Emperor Hirohito spoke of how cruel the bomb was within weeks of its aftermath, he could not have foreseen the damage and ruin it would cause not only to survivors, but to the children of survivors as well.

How the Atomic Bomb Affected Cancer Genetics

As mentioned earlier, one of the primary increased health risks from exposure to the atomic bomb's radiation is cancer. Exposure to the ionizing radiation released from the bomb has not only lead to a greater rate of cancer for those directly involved, but also for their children as well. Mr. Yoshimoto has conducted much of the leading research regarding this. Yoshimoto ran studies on both children that were fetuses when their mother's were exposed to radiation, and children that were conceived after their parents had been exposed. [1] In his studies, Yoshimoto found that 18 children that were fetuses out of 1630 had cancer between the periods of 1950 to 1980. [1] This amount is significantly greater than with subjects without such exposure. Further, he also found that parents exposed to at least 0.30 Gy would go on to have children with an increased risk of cancer. [2]

Although Yoshimoto's findings seem to support an increased risk of cancer from exposure to ionizing radiation, other studies have found contradicting results. One such experiment found that from 1947 to 1954, children born from parents exposed to the atomic bomb attacks in Japan did not have a significantly higher chance of being born with cancer.

Other Effects from Radiation Exposure

Two other significant effects from radiation exposure are mental retardation and birth defects. There is significant evidence to support that children that were fetuses during the bombings were born with a much greater chance of both mental retardation and having a head size much below average, which signifies having little brain development. [3] In a study done by Mr. Miller, he found that children whose parents were within 1200 meters from the center of the bombings all were born with mental retardation. With that said, for mothers that were outside of 1200 meters, there was no increased risk of mental retardation for their children. [3]

Another drastic harm caused by the radiation from the atomic bomb is birth defects; however, research remains inconclusive as to whether or not exposure to radiation has had a direct effect. In Mr. Schull's research, he has concluded that the increased risk from exposure is too small to be statistically significant. [4]


The dropping of the atomic bombs on Hiroshima and Nagasaki will always be remember as one of the most fatal and horrific attacks on man-kind. The fact that after the dropping of the second bomb Japan was forced to surrender shows that magnitude of such a weapon. However, as we transition into an age with greater nuclear technology and weaponry, it will be important to keep in mind the drastic effects that come from using these weapons. As seen in this paper, these bombs not only affect those directly involved, but also can have lingering effects for generations to come.

© Jay Fuster. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] Y. Yoshimoto, H. Kato, and W. J. Schull, "Risk of Cancer Among Children Exposed in Utero to A-Bomb Radiations, 1950-1984," Lancet 332, 665 (1988).

[2] Y. Yoshimoto, "Cancer Risk Among Children of Atomic Bomb Survivors: A Review of RERF Studies," J. Amer. Med. Assoc. 264, 596 (1990).

[3] R. W. Miller, "Effects of Ionizing Radiation from the Atomic Bomb on Japanese Children," Pediatrics 41, 257 (1968).

[4] W. J. Schull, "The Children of Atomic Bomb Survivors: A Synopsis," J. Radiol. Prot. 23, 369 (2003).