There is overwhelming evidence that life has evolved over thousands of millions of years. The ancestors of modern organisms, as well as whole groups that are now completely extinct, have been found in great abundance as fossils. The main processes responsible for evolutionary change, such as variation and natural selection, have been repeatedly observed and verified in natural populations and in laboratory experiments. All the features of living organisms, including those discovered in the recent advances in molecular biology, are readily explained by the principles of evolution. Any scientific theory that provides a clear mechanism, offers a broad explanation of natural phenomena, receives strong support from observation and experiment and that is never refuted by careful investigation is usually called a “fact”. The cell theory of organisms, the germ theory of infection, the gene theory of inheritance and the theory of evolution are all facts. Teaching alternative theories as though they had equivalent scientific status is a perversion of education that damages children’s ability to understand the natural world. In particular, creationism is a religious doctrine long since known to be a fallacious account of Earth history that has no scientific standing and cannot be represented as a credible alternative to evolution. Evolution is the single most important principle of modern biology and the foundation of any sound biology curriculum.