Genetic engineering is the altering of the genetic material of living cells in order to make them capable of producing new substances or performing new functions. When the genetic material within the living cells, i.e. genes are working properly, the human body can develop and function smoothly. However, should a single gene--even a tiny segment of a gene go awry, the effect can be dramatic: deformities, disease, and even death. In the fast 40 years, amazing discoveries and development of revolutionary new techniques have allowed scientists to learn a great deal about how genes work and how they are linked to disease.

In the 1950s, largely as the result of the pioneering work of James Watson (1928-) and Francis Crick (1916-), scientists discovered the structure of deoxyribonucleic acid (DNA) molecules and how DNA stores and transmit genetic information. Scientists found that the precise arrangement (or sequence...