 It might be helpful to consider an analogy with smoking. Smoking cigarettes, on its own, is neither a necessary nor a sufficient condition for developing lung cancer, since there are people who smoke like chimneys who never develop lung cancer and live perfectly healthy lives to a ripe old age; and there are people who have never smoked a cigarette in their whole life who develop lung cancer. Yet it is generally agreed nowadays that smoking cigarettes is a cause of lung cancer. This is because smoking (in combination with other factors such as genetics, diet and exercise) makes it significantly more likely that a person will develop lung cancer, or so the studies suggest. Likewise, we might think that consumption of pornography will be a cause of violent sexual crime (or of sexist attitudes and behavior more generally) if there is good evidence to suggest that consumption of pornography increases the incidence of sexual violence or sexist behavior, holding fixed other known causes of these harmful states of affairs.[6]