More than half a million people worldwide have purchased Direct-to-Consumer (DTC) genetic tests. A survey conducted in the US in 2010 indicated that 70–80% of respondents are willing to pay for DTCs1 even if the results do not have immediate clinical value. A 2009 online survey of more than 1000 social networking users found that 64% of them were interested in buying a genetic test to obtain useful health information.2

By providing individuals with information about their genetic predisposition to a variety of diseases, DTCs are supposed to influence healthcare use and to motivate beneficial behavior change. However, the few available studies that have investigated the users’ response to DTCs have found that:

  • - people generally adapt well to the information received,3 having no significant short term effects in ‘psychological health, diet or exercise behavior, or use of screening tests’.4

  • - people do not significantly change their behavior as the result of genetic risk information.4

  • - changes are related to a subjective interpretation of risk.5

A 2010 Cochrane Collaboration systematic review, concluded thus: ‘Claims that receiving DNA-based test results motivates people to change their behavior are not supported by evidence’.6

Choices are guided by cognitive and emotional processes, so what is it that takes place in our mind that disposes us to spend money on information that we’ll never use? Other than the well-known statistical illiteracy,7 we argue that the decision to buy a genetic test may be a consequence of a self-signaling action. A self-signaling action is one chosen partly to secure good news about one’s traits or abilities, even when the action has no causal impact on these traits and abilities.8 Moreover, thanks to the optimistic bias9 we believe that we are less at risk of experiencing a negative event than are other people. Confirmation bias does the rest, inducing the tendency to search for, interpret, or recall information in a way that only serves to confirm our beliefs or hypotheses.10

These observations highlight the importance of increasing the knowledge and awareness of consumers, rather than regulating the DTC market, so as to render them able to use the acquired knowledge in an effective way instead of transforming it into biased (and useless) knowledge.