Far more significant for the public understanding of science is the fact that people tend not to think of risk in purely statistical terms. Surveys show that most people have a good grasp of the relative chance of death they face from various hazards. For example, they know that in any normal year heart disease kills more people than botulism. However, when asked about the overall risks that these hazards pose to their well-being, people's judgements extend far beyond the statistical chances of dying. We find risks more acceptable if we can choose whether or not to take them, if we can control our level of exposure and if the benefits are clear and immediate.
Mobile phones are an obvious example.
Despite the sensational media stories, most people have carried on using them. On the other hand, we object to hazards that are imposed on us without our consent, that affect the young or could cause a major catastrophe, or when risks and benefits are inequitably distributed across society. Nuclear energy is one example. Often, controversies about risk seem to be more about politics and ethics than about the science. This, I suspect, is the case with the mapping of the human genome.