Biomedical research, on the one hand, contributes to important goals from generation of knowledge about the human body to the development and testing of therapeutics of all kinds. On the other hand, it can produce serious and sometimes unforeseeable consequences. In the ethical analysis of these two aspects of biomedical research, two important argumentative strategies play a major role. First, slippery slope arguments are used to warn of potential risks and to highlight knowledge-based limitations. Second, a dual-use problem describes the (...) challenge that already established techniques can be used for both morally wrong and morally right purposes. These two argumentative strategies appear to share several similarities, which will be investigated in this article. For this purpose, the article will first provide clear working definitions for both types of argument. This lays the foundation for the further ethical analysis. In a second step, and in order to investigate the similarities and differences of the argumentative strategies with an example from current ethical debates, CRISPR-Cas9, a currently very promising tool of genome editing, will be examined. The extent to which the possible applications of this genome editing tool can be addressed by slippery slope arguments or the dual use problem will be investigated. For this purpose, selected studies involving the use of CRISPR-Cas9 will be examined. Based on this two-step, analytic and example-based comparison of slippery-slope argumentation and dual-use considerations, the article will detail the ethically relevant difference between the two argumentative strategies and at the same time contribute to the ongoing ethical debate about CRISPR-Cas9. (shrink)