What is a knock-out mouse? Why is “golden rice’ controversial? How does natural cloning happen? The 'Why Science Matters' series demonstrates how the science we learn at school is important in every aspect of our everyday lives. Using case studies and investigations, the series describes the development of science and technologies that can improve our lives – or lead to new scientific challenges and controversies. In 'Using Genetic Technology' we find out about the potential benefits and risks of technologies such as gene therapy, which have to be balanced against one another. We learn how characteristics of living things are the combined result of a number of genes, and how scientists can alter an organism by altering its genetic make-up. We discover how it could become normal to grow crops or farm animals to produce drugs and medicines, in the same way that we farm them for food, milk, or wool today.