Screening has become central to the effective prevention of several diseases, but implementation suffers from difficulties with targeting and rates of compliance. Such issues are also complicated by the need to consider legal provisions regarding confidentiality of patients and other human rights issues. Screening has been an inexact science in relation to, e.g., faecal occult blood testing for colorectal cancer, false positive and false negative tests for HIV, and there have been inadequate quality controls in breast cancer screening programmes. The public need to be made aware of what the screening programmes really offer, balanced against the expectations they may have. There needs to be a clearer understanding of the nature of the contractual and other legal rights of patients/consumers as against providers. A positive screening test may carry adverse consequences as well as benefits. It could alert an insurance company to a risk and lead to additional weighting or even outright rejection for life insurance policies. Job prospects may also be affected for employees. The method of informing patients in relation to screening and screening failure has already been considered by the courts. Realistic information about both screening and treatment efficiency needs to be offered to patients so that they can have a real understanding of what can and cannot be achieved by current science. The development of understanding of the human genome makes the need for clearer legislation in this are more urgent.