PROJECT SUMMARY/ABSTRACT Citizen science initiatives have exploded in recent decades and now number in the thousands worldwide. Citizen science generally refers to an approach to scientific inquiry in which members of the public participate in one or more steps of the research process other than, or in addition to, providing data or biospecimens for analysis. Citizen science activities that study biomedical questions and are designed, controlled, and executed with minimal to no input from institution-based scientists are sometimes described as biohacking. Following the recent discoveries of inexpensive and relatively easy-to-use gene editing tools, genomic experimentation in particular has become popular among biomedical citizen scientists. Although many of their activities might be considered relatively safe, others?for example, self- experimentation with unregulated gene therapies?are associated with elevated risk of harms and unique ethical concerns. Yet, many biohacking activities are outside the reach of federal ethics review requirements and do not have access to institutional mechanisms of ethics oversight, contributing to what has been described as an ?ethics gap? in citizen science. The time is ripe for a critical examination of the ethical oversight of biomedical citizen science, especially genomic biohacking activities that are increasingly common across citizen science settings. Some scholars have proposed new mechanisms of ethics review for citizen science. To date, however, the ethical attitudes and preferences of biomedical citizen scientists have not yet been systematically identified. The absence of these data undermines any attempt to develop solutions to the problem of the ?ethics gap? since there is no empirical basis for knowing whether the proposed mechanisms will align with the ethos or experience of participants and therefore will be acceptable and useful to them. The proposed research will collect this critical, missing evidence and use it to evaluate mechanisms of ethics oversight of citizen science. Specifically, Aim 1 will identify the role of ethics in genomic biohacking from the perspective of participants through semi-structured qualitative interviews of 30 genomic biohackers representing a spectrum of experiences. Next, Aim 2 will evaluate ethics review of genomic biohacking activities by institutional review boards and alternative oversight mechanisms on the basis of their consistency with the ethical attitudes and preferences of biohackers identified in Aim 1. The contribution of this research will be significant because it will lay the essential groundwork on which to build ethics tools and resources for genomic and other biomedical citizen scientists.