STUDY QUESTION: What are the opinions of professionals in the field of genetics, reproductive science and metabolic diseases on the development of mitochondrial replacement technologies to be used in the context of medically assisted reproduction? SUMMARY ANSWER: Although concerns regarding safety remain, interviewees supported the development of nuclear transfer techniques to help women who are at risk of transferring a mitochondrial DNA disease to their offspring conceive a genetically related child. WHAT IS KNOWN ALREADY: Technological developments in the field of nuclear transfer have sparked new interest in the debate on the acceptability of the use of donor oocytes to prevent the transmission of mitochondrial diseases. For example, in the UK, extensive public consultations have been done to investigate whether such techniques would allow the passing of a law that involves making changes to a human oocyte or embryo before transfer to a woman's body. Until now, continental European countries seem to await the outcome of the British debate before themselves considering the arguments for and against this technology. STUDY DESIGN, SIZE, AND DURATION: We interviewed 12 professionals from Belgium and The Netherlands. PARTICIPANTS/MATERIALS, SETTING, AND METHODS: We conducted 12 interviews with fertility specialists, scientists, clinical geneticists, a pediatrician specialized in metabolic diseases and a specialist in metabolic diseases. The profiles of the interviewees varied but all had experience with mitochondrial diseases, either in treating patients or in providing counseling to patients or to prospective parents. The interviews were conducted face-to-face and took 30-45 min. The language of the interviews was Dutch. We analyzed the transcript of these interviews using QSR NVIVO 10 software to extract themes and categories. MAIN RESULTS AND THE ROLE OF CHANCE: This study has shown that, although amongst the professionals we interviewed there was support for the development and deployment of nuclear transfer, this support does not necessarily correspond to uniform opinions about the importance of having a genetically own child or the contribution of mitochondrial DNA to essential characteristics of an individual. LIMITATIONS, REASONS FOR CAUTION: In translating the quotes from Dutch to English some of the linguistic nuances may have been lost. We only interviewed 12 individuals, in two countries, whose view may not be representative of existing values and opinions that may be held by professionals worldwide on this matter. To further explore the issue at hand, a subsequent investigation of the opinions of people affected by mitochondrial diseases and of the general public is necessary. WIDER IMPLICATIONS OF THE FINDINGS: With this study we have demonstrated there is in principle support for the nuclear transfer technique from Dutch and Belgian professionals. Further research, both scientific and ethical, is needed to define the modalities of its possible introduction in the fertility clinic.