Abstract Background Although translational research for drug development can provide patients with valuable therapeutic resources it is not without risk, especially in the early-phase trials that present the highest degree of uncertainty. With the extraordinary evolution of biomedical technologies, a growing number of innovative products based on human cells and gene therapy are being tested and used as drugs. Their use on humans poses several challenges. Methods In this work, we discuss some ethical issues related to gene and cell therapies translational research. We focus on early-phase studies analysing the regulatory approach of Europe and the United States. We report the current recommendations and guidelines of international scientific societies and European and American regulatory authorities. Results The peculiarity of human cell- or tissue-based products and gene therapy has required the development of specific regulatory tools that must be continually updated in line with the progress of the research. The ethics of translational research for these products also requires further considerations, particularly with respect to the specificity of the associated risk profiles. Conclusions An integrated ethical approach that aims for transparency and regulation of development processes, the support of independent judgment in clinical trials and the elimination of unregulated and uncontrolled grey areas of action are necessary to move gene and cell therapy forward.