DNA copying is an essential part of reproduction because it is a basic event in the creation of new cells. Cells use chemical reactions to build copies of their DNA, and this copying is accompanied by the creation of an additional cellular apparatus. The DNA copies then separate, each with its own cellular apparatus, effectively allowing a cell to divide and give rise to two cells. Without DNA copying, the new cell would not have any organised cellular structure for maintaining life processes.

Moreover, the DNA copying mechanism cannot be absolutely accurate, and the resultant errors are a source of variations in populations of organisms. These variations are useful for ensuring the survival of the species and form the basis for evolution.