On the simplest scale, genetic engineering allows scientists to manipulate the genes within an organism. Scientists will add, subtract, and/or rearrange the DNA sequence within an organism to change it from its original form. There are three main types of genetic engineering: gene therapy, gene splicing, and cloning.
Gene therapy is used to correct faulty or defective genes. Gene splicing is used to modify plants in order to produce the best plant. Cloning is used to recreate genetic material.
All of genetic engineering has been criticized. Activists have stated that genetic engineering is allowing mankind to pick and choose what exists in regards to humans, animals, and food. They believe that this throws the balance out of the natural order of things. Dog breeders have used genetic engineering to rid some breeds of undesirable traits and boost desirable ones. The biggest argument is that mankind is now "playing God."
Proponents of genetic engineering state that it can help mankind in as multitude of ways. Defective genes in unborn babies can be manipulated or removed. Plants will grow better, stronger, and more plenteous. Animals raised for meat will have more muscle mass.