The diagnostic genetic testing process has certain unique ethical features and deserves special consideration. The purpose of this study was to determine through empirical research, using focussed interview, what ethical issues are involved in the diagnostic genetic testing process. This article describes views and perceptions of adult patients, parents of child patients and various personnel groups (n=30). The ethical issues were analysed classified into three main categories: a) personnel characteristics, including personality, professional skills, morals and values; b) realization of ethical principles in the examination process, with subcategories of knowledge, autonomy, data protection and equity; and c) consequences of genetic testing, including patients' control over their own lives, manifestation of heterogeneity and outlook on the world. Problematic ethical issues in all three main categories were described in a more many-sided way by parents and personnel than by adult patients. In the future, attention should be paid to the content areas highlighted by the study, in both clinical practice and further studies.