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Therapeutic cloning, or somatic cell nuclear transfer (SCNT), is a procedure that can be used to replace and repair damaged or defective tissue. The procedure is accomplished by producing cloned embryos to create stem cells to grow the replacement tissue. This cloning technique can be used to grow replacement hearts, livers, and other major organs. Therapeutic cloning can also keep a patient off an organ waiting list and not having to worry about the body rejecting a donated organ. These stems cells can also provide healthy nerve cells and replacement skin for burn patients.
So if therapeutic cloning can provide people with new organs and replacement skin, why is not being done all over the world? This is because there are some drawbacks with the use of therapeutic cloning.
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Inability to Use Adult Stem Cells Limits Use
The traditional cloning process using human embryos looked to have very beneficial outcomes. Experiments using adult stem cells do not work as well. Therapeutic cloning is a new field and the application of these adult stem cells is very limited. Embryos have been proven to have a greater flexibility than the adult stem cells. More research will have to be done before adult stem cells can be used to cure or treat any diseases.
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Stem Cells Can be Unstable
Since therapeutic cloning is new there are many deficiencies that have to be overcome. In many cases, stem cells sometimes mutated and are then rejected by the recipient's body. Other studies have shown that stem cells used in animals later begin to develop tumors. This raises the concerns of long-term use of stem cells for humans.
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Dependent on Human Donors
It takes many eggs to produce a usable stem cell--in most cases more than a hundred. If a cure for a specific disease is needed and therapeutic cloning is used, it could take over 1.5 billion eggs (or more depending on the disease) to cure every person with the disease.
To get eggs for therapeutic cloning, there has to be donors. For women, donating eggs is very painful and costly. And with the limited amount of eggs a woman can donate at a time, over 500,000 women would have to be willing to do so. This number is not very realistic and limits the usability of the procedure. This is also another reason why using adult stem cells may be preferred over embryos.
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Controversy over Killing Embryos
There is much debate over the morality of killing human embryos. Pro-life supporters believe that a person exists at conception while some believe that the somatic cell nuclear transfer during therapeutic cloning also creates life. During the process of extracting stem cells, the embryo is killed. Pro-life supporters believe this is murder and to kill one person to cure another can not be justified.
- National Human Genome Research Institute: Therapeuitc Cloning - www.genome.gov/25020028#al-14