||Genetic testing is carried out for different purposes: diagnostic, predictive, and reproductive. Diagnostic testing is complementary to other diagnostic techniques, yet it raises issues of confidentiality, privacy, data security, accidental findings, the right not to know and the duty to communicate valuable information to genetically related relatives. Predictive and reproductive testing are even more problematic. Predictive testing may raise different issues at the individual and population level (screening). At both the individual and the population level, it raises the issues of voluntariness, informed consent, legislative protection against discrimination. Reproductive testing raises issues of eugenics, nondirectiveness in reproductive decisions, and reproductive rights. Inequalities in access to testing technology and genetic counselling raise issues of justice. Other questions concern genetic knowledge itself: when is a genetic test sufficiently sensitive and reliable, when are its results adequately interpreted, in order for the test to be made available to individuals, commercialised, or offered to the population at large by health care institutions.