The German Law for Prevention of Genetically Diseased Offspring (Das Gesetz zur Verhütung erbkranken Nachwuchses) was enacted in 1933. It allowed forced sterilization of patients who had been diagnosed with certain so-called hereditary diseases. Drawing on patient files from the city of Göttingen, this article provides new research results about the practice of forced sterilization of men in the Third Reich. Results show that around 1000 men were sentenced to sterilization by the local hereditary health court (Erbgesundheitsgericht). In this article, some aspects of the operation and "refertilization" are reconstructed.