In genetics, to clone an organism is to make an exact copy of its DNA. Cloning is commonly done on small organisms, mostly plants, and on animals, such as the famous sheep called Dolly. The most controversial aspect of cloning is whether or not it should be done on humans. This includes the cloning of any and all human tissue, including organs.
In January of 2008, scientists Wood and Andrew French claimed to have successfully created five healthy human embryos from DNA taken from adult cells. The embryos were destroyed, however, because reproductive cloning is currently illegal in the United States. The advantages and disadvantages of cloning humans have been discussed in great detail, and the arguments are ongoing.
British biologist J.B.S. Haldane is given credit for having coined the word "clone" during a speech in 1963. In 1966, scientists Marshall Niremberg, Heinrich Mathaei, and Severo Ochoa broke the genetic code, allowing for studies on genetic engineering. The first gene was isolated in 1969 and the first recombinant DNA molecules, a combination of the DNA from two different organisms, were created in 1972. In 1977, a German biologist created mice with a single parent. By 1979, Karl Illmensee claimed to have successfully cloned three mice.
The method of nuclear transfer was created in 1983, and in 1984, Danish scientist Steen Willadsen cloned a sheep from embryo cells, which is considered the first true cloning of a mammal using nuclear transfer. In 1986, it was discovered that cloning could be done by using the nucleus of an adult cell, not just embryo cells. This eventually led to Ian Wilmut's cloning of the infamous sheep "Dolly" in 1996. Dolly was the first animal cloned from adult cells.
Much debate ensued as to the medical and ethical value of cloning, and in 1997, President Clinton passed a five-year moratorium on human cloning research until the National Bioethics Advisory Commission could review the issues involved. Since that time, many more animals have been cloned, and the process for cloning has been refined and improved. In 2002, the National Bioethics Advisory Committee put out a report stating the following:
First, that cloning to produce children is unethical and should be illegal. Second, that cloning humans for research should either be strictly regulated by the federal government or banned entirely, and third, that a federal review of current and projected projects regarding human cloning be undertaken, with the ultimate goal of creating some ethical and scientific policies and guidelines for the field of cloning.
Cloning a human would create a baby who is genetically identical to another human being. This would be achieved through assisted reproductive technology, called nuclear transplantation.
According to the members of the Panel on Scientific and Medical Aspects of Human Cloning, cloning is performed by removing the nucleus of a new human egg and replacing it with the nucleus of an adult cell. This egg is then stimulated to begin dividing and growing. Ideally, it will then become a blastocyst, which is made up of 150 cells.
At this point, the healthy blastocyst would be placed in a uterus, where it could implant and grow into a foetus, and eventually, a newborn baby. This baby would have the same genes as the nucleus of the adult cell mentioned above. However, scientists do not think the baby would grow into an exact copy of the adult, due to differences in the baby's environment.
Non-reproductive cloning is done to clone stem cell lines. In this case, the steps above are followed, but the blastocyst is not implanted in the uterus. Instead, once the blastocyst has formed, cells are taken from it and used to create stem cell lines for further research. Stem cells are not specialised, which means they can grow into anything and renew themselves over and over again and lend themselves to a wide range of uses. Many scientists consider stem cells important tools for medical research.
There are many things to be cautious about when considering whether or not to clone humans. Diversity in genes is beneficial to our society. Adaptation in genes allows human beings to strengthen themselves against diseases and the environment. Cloning would limit this ability severely.
Copying something generally weakens it, and scientists have found this true of cloning. All cloned animals have died early of diseases or genetic issues.
The cloning of human body tissue also brings up several ethical questions. Who will own the tissue? The carrier of the DNA, or the scientists who create it? Will the monetary costs of cloning be worth the final result?
Finally, there are those who worry that cloning allows man to "play God." Is it really a good idea for one human to be able to create another human?
One benefit of cloning human tissue is that if researchers can grow vital organs, they can be used to replace ailing organs. For example, if heart disease destroys a patient's heart, an exact replica can simply be "grown" to replace it.
Human cloning can also be a solution for infertile couples, even allowing the couples to create a child with certain features. Because cloning allows for the manipulation of genes, embryos can be created free of inherited genetic disorders or predispositions.
The cloning of human tissue could also be used to treat cancers, and even for plastic surgery.
Science fiction gives rise to many misconceptions about cloning. Some common misconceptions include the idea that people who are cloned would be exactly like their genetic donor. This is not true, because environment and experiences shape who you become. Others think that cloned people would be perfect, that all imperfections would be "weeded out." Again, this is not scientifically possible. Others think that clones would go "crazy," as in the movie "Godsend," where a cloned child caused havoc for his parents. Some think that cloning means humans would no longer believe in God, and that society as a whole would go downhill as a result. All of these are misconceptions, rumours, or wild theories.