During the mid-1950s, Pauling started campaigning for world peace by discussing the science behind nuclear weapons and the potential health hazards of nuclear fallout. In 1963 he was awarded the 1962 Nobel Peace Prize for his efforts. In the late 1950s and 1960s, Pauling occasionally mentioned molecular disease when talking about the repercussions caused by nuclear fallout and typically drew one connection between the two topics – genetic mutations and their resultant birth defects. By discussing radiation’s infliction of human suffering through mutagenic effects and potential health hazards, Pauling substantiated his call for world peace and a ban on nuclear weapons testing.

To clarify his point about molecular diseases, Pauling discussed sickle cell anemia. By this time, Pauling could draw upon the experimental work completed by Ingram in 1956 and 1957 in which Ingram had ascertained the difference between sickle cell hemoglobin and normal hemoglobin. Ingram had found that of the 300 amino acid residues in hemoglobin, only one differs; whereas normal hemoglobin has a glutamic acid at one of its loci, sickle cell hemoglobin has valine at the same locus. According to Pauling, Ingram’s work gave credence to the idea that a gene mutation altered the amino acid sequence of hemoglobin, which in turn changed its structure and caused sickle cell anemia.

Although the historical circumstances behind the gene mutation from normal to sickle cell hemoglobin could not be determined, Pauling used the example of sickle cell anemia to show how the replacement of one amino acid produced molecular disease in humans. In other words, if the replacement of one amino acid in hundreds could cause the deadly disease sickle cell anemia, then the potential hazard from gene mutations caused by nuclear fallout could cause comparable suffering or worse.