Abstract: Gamete donor anonymity has become an increasingly active area of legislative, bioethical, and empirical interest over the last decade or so. This chapter begins by detailing the very different status of gamete donor anonymity, contrasting the United States (where the law does not prohibit it) with the rest of the world (where it has been largely prohibited by law) and examining the effects of these policies. The chapter then examines the major arguments that have been offered in favor of and against mandating nonanonymous gamete donation. In particular, it focuses on the effects of removing anonymity on supply and arguments in favor of ending sperm donor anonymity based on the welfare of donor-conceived children or rights claims by them. The chapter also more briefly considers ethical and legal issues related to donor compensation, accidental incest, information reciprocity between donors and recipients, and reproductive tourism.