The ability to generate human tissues in vitro from stem cells has raised enormous expectations among the biomedical research community, patients, and the general public. These organoids enable studies of normal development and disease and allow the testing of compounds directly on human tissue. Organoids hold the promise to influence the entire innovation cycle in biomedical research. They affect fields that have been subjects of intense ethical debate, ranging from animal experiments and the use of embryonic or fetal human tissues to precision medicine, organoid transplantation, and gene therapy. However, organoid research also raises additional ethical questions that require reexamination and potential recalibration of ethical and legal policies. In this Review, we describe the current state of research and discuss the ethical implications of organoid technology.