A controversial issue of the twenty-first century is the possible application of new techniques in genetic engineering to produce human clones. Up until now genetic engineering and cloning has been used to clone plants, unicellular organisms, amphibians and simple mammals. This has led to significant advances in agriculture, industry, and medicine. Newer techniques in genetic engineering have enabled scientists to clone more complex mammals and opened up the possibility of cloning humans. Although there are many potential benefits to this technology, the prospect of cloning humans has raised many practical, ethical and religious dilemmas that are currently being debated by society. As of now, the actual cloning of humans does not seem likely to occur in the foreseeable future. .
Genetic engineering is the changing of an organism's DNA, genetic material to eliminate unwanted traits or to produce desirable traits. The earliest form of genetic engineering dates back to the scientist Gregor Mendel who did experiments with peas. He bred only the peas with the most desirable traits in order to achieve a healthier and stronger pea (McCuen 8). This method, called selective breeding, is still used today with plants and animals in order to increase food production. Corn plants are selectively bred in order to produce a larger tastier kernel. Another type of genetic engineering called hybridization or crossbreeding involves breeding animals of different species in order to obtain the most desirable traits of both. Male donkeys are crossbred with female horses to produce mules, which are good work animals (Levine 1). .
In 1938, Hans Speman proposed cloning a mammal by transplanting an adult cell's nucleus into a fertilized egg. This process is called nuclear transfer and was initially used to clone a frog in 1952 (Sinha 59). Using this process, nuclear DNA from the body cell of a donor frog was injected into the egg cell of a recipient frog whose nuclear genetic material was removed.