In 1903 the Wright brothers flew for the first time in a machine heavier than air. They soared 30 metres above land for 12 seconds. No one would have imagined that this technology would one day lead to the manufacture of aircraft which would cross the sound barrier and transport hundreds of people across the world. Today, another earthshattering scientific achievement has been made which will revolutionise biotechnology: man has been able to clone a mammal from an adult cell in the laboratory. In addition, it is now possible to replace or introduce new genes into a cell in the progress of an individual. This has been possible because of the tremendous progress made in molecular and cellular biology and our ability to study the genetic material - DNA - more closely.