Eugenic ideas influenced medicine, psychiatry, sexual science, and legal studies well into the mid-20th century. This lasting impact was based on the notion that reproduction could be deliberately influenced to solve social problems. In this context, sexuality was once again brought to the forefront, and the regulation of sexual behavior was legitimized. Eugenics, both a science and an ideology, has reinforced racist tendencies through the belief that human genetic material could and should be improved through selection. By categorizing life as "worthy" or "unworthy," it contributed to the exclusion of certain individuals. This study reveals the contradictions and ambiguities of these developments in Switzerland and analyzes the eugenic connections between an increasingly liberal approach to sexuality.