An Oklahoma statute, the Habitual Criminal Sterilization Act, allows the forced sterilization of any “habitual criminal” within the state. The statute defines a “habitual criminal” as a person who, having been convicted two or more times for crimes “amounting to felonies involving moral turpitude” either in Oklahoma court or in a court of any other state, is thereafter convicted of such a felony in Oklahoma and sentenced to prison within Oklahoma. Skinner (defendant) was convicted in 1926 of stealing chickens and sentenced to prison in Oklahoma. In 1929, Skinner was convicted of robbery with firearms and sentenced to prison. In 1934, he was convicted again of robbery with firearms and again incarcerated in Oklahoma. He was confined there in 1935 when the Sterilization Act was passed, and in 1936, the Attorney General of the State of Oklahoma, (plaintiff) instituted proceedings against him. Skinner challenged the act as unconstitutional under the Fourteenth Amendment’s Equal Protection Clause. At his jury trial in Oklahoma state court, the court instructed the jury to consider only whether a vasectomy would be detrimental to Skinner’s health. The jury answered in the negative. The Supreme Court of Oklahoma affirmed a judgment directing that a vasectomy be performed on Skinner. The United States Supreme Court granted certiorari.