An extensive literature describes the legal impact of America's eugenics movement, and the laws mandating sterilization, restriction of marriage by race, and ethnic bans on immigration. But little scholarship focuses on the laws adopted in more than 40 states that were commonly referred to as "eugenic marriage laws." Those laws conditioned marriage licenses on medical examinations and were designed to save innocent women from lives of misery, prevent stillbirth or premature death in children, and save future generations from the myriad afflictions that accompanied "venereal infection." Medical journals, legal journals, and every kind of public press outlet explained the "eugenic marriage laws" and the controversies they spawned. They were inextricably bound up in reform movements that attempted to eradicate prostitution, stamp out STIs, and reform America's sexual mores in the first third of the 20th century. This article will explain the pedigree of the eugenic marriage laws, highlight the trajectory of Wisconsin's 1913 eugenic enactment, and explore how the Wisconsin Supreme Court case upholding the law paved the way for the majority of states to regulate marriage on eugenic grounds.