With screening the natural course of disease should be altered to reduce mortality from that disease. Screening offers very little benefit but has many disadvantages like false-positives, overdiagnosis and psychological distress. The advocates of screening overestimate the importance of the disease and the effects of screening but neglect the disadvantages. But also potential participants and medical doctors overestimate the effects of screening. Although considered important the still valuable criteria by Wilson and Jungner are neglected by researchers and committees that approve screening. Even in the situation that doctors disapprove screening healthy people are willing to undergo body-scans although nobody knows how to deal with the many abnormalities that are detected. Screening programmes should be evaluated against other interventions and not simply by making models with a lot of unproven assumptions. And most of all the potential participants have to informed about the potential disadvantages and the small effects on health.