Genetic engineering refers to the process of altering genes, the building blocks of life, by a biochemical manipulation in order to produce an altered or a completely new organism. This biochemical procedure, developed in the early 1970s, is termed recombinant DNA 1 technology because segments of genetic material from one cell are incorporated into another. The technology of genetic engineering is currently being used in many areas with great usefulness. The pharmaceutical industry has already produced several products for human therapy, such as human hormones and enzymes. Ingenious vaccines have been developed. Insertion of genes in important crop plants have increased resistance to disease and other forms of stress and increased nutritional value. Bacteria have been genetically engineered to decompose oil spills.