The progress in molecular genetic research leads to an increased availability of predictive diagnosis of inherited diseases. However, the prediction of an incurable illness is inevitably related with severe psychic conflicts. Based on the relevant literature, the psychological implications of predictive diagnostics are outlined, and counselling strategies for persons vulnerable for an inherited disease are summarized. In spite of numerous studies with persons at risk the prediction of the individual reaction remains rather difficult. Unconscious expectations play an essential, but underestimated role for the test motivation and coping strategies. Relieving the pressure of time supposed by most of the risk persons seems necessary to allow a deeper understanding of motivation and development of sound coping strategies. After disclosure of the test result, an ongoing counselling should be offered to all family members.