Contrasting ethical and legal arguments have been made concerning neonatal male circumcision (NMC) that merit the first systematic review on this topic. We performed PRISMA-compliant keyword searches of PubMed, EMBASE, SCOPUS, LexisNexis, and other databases and identified 61 articles that met the inclusion criteria. In the bibliographies of these articles, we identified 58 more relevant articles and 28 internet items. We found high-quality evidence that NMC is a low-risk procedure that provides immediate and lifetime medical and health benefits and only rarely leads to later adverse effects on sexual function or pleasure. Given this evidence, we conclude that discouraging or denying NMC is unethical from the perspective of the United Nations Convention on the Rights of the Child, which emphasizes the right to health. Further, case law supports the legality of NMC. We found, conversely, that the ethical arguments against NMC rely on distortions of the medical evidence. Thus, NMC, by experienced operators using available safety precautions, appears to be both legal and ethical. Consistent with this conclusion, all of the evidence-based pediatric policies that we reviewed describe NMC as low-risk and beneficial to public health. We calculated that a reduction in NMC in the United States from 80% to 10% would substantially increase the cases of adverse medical conditions. The present findings thus support the evidence-based NMC policy statements and are inconsistent with the non-evidence-based policies that discourage NMC. On balance, the arguments and evidence reviewed here indicate that NMC is a medically beneficial and ethical public health intervention early in life because it reduces suffering, deaths, cases, and costs of treating adverse medical conditions throughout the lifetimes of circumcised individuals.