States and municipalities have attempted to limit the teaching of evolution based on religious objections. Such a governmental restriction raises First Amendment concerns, because it supposedly stifles free speech and dictates what speech is permissible. The father of the theory of evolution was naturalist Charles Darwin, whose writings in the mid-1800s took the scientific world by storm, especially with the publication of On the Origin of Species. Evolution is a widely accepted scientific theory premised on the view that the earth and its life are the product of change over long periods of time. Evolution seemed to call into question the validity of the biblical creation story that portrays God as the divine creator, instead arguing that the state of the human form is the result of natural forces over millions of years.