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How Human Cloning Will Work
by Kevin Bonsor

Nothing really prepared the world for the 1997 announcement that a group of Scottish scientists had created a cloned sheep named Dolly. There's little doubt that within the next decade, we will hear a more shocking announcement of the first cloned human. Several groups have developed plans to be the first to do so, and the research is already underway to make it happen.

Talking to yourself will take on a whole new meaning when cloning is made possible.

Until now, the idea of human cloning has only been possible through movie magic, but the natural progression of science is making human cloning a true possibility. We've cloned sheep, mice and cows, so what's to stop scientists from cloning a human? Some countries have set up laws banning cloning, but it is still legal in many countries. It will cost tens of thousands to hundreds of thousands of dollars, but there will always be people willing to spend that type of money to be a part of history.

Critics, backed by studies, say cloning is still a dangerous technology that can cause serious defects in the clones. The low success rates of cloning efforts of about 3 percent has also raised questions about the morality of cloning a human. In this edition of How Stuff WILL Work, we will look at the process that could be used to clone humans, why we would want to clone ourselves and the controversy surrounding cloning.

Me, Myself and My Clone
In January 2001, a small consortium of scientists led by Panayiotis Zavos, a former University of Kentucky professor, and Italian researcher Severino Antinori said that they planned to clone a human in the next two years. At about the same time, the New York Post reported a story about an American couple who planned to pay $500,000 to Las Vegas-based Clonaid for a clone of their deceased infant daughter.

These scientists may be chasing glory in the name of science. Whatever their motivation, it's likely that we will see the first cloned human baby appear on the evening news perhaps as soon as 2005. Scientists have shown that current cloning techniques work, but only rarely do they succeed in creating a cloned embryo that makes it through birth.

If human cloning proceeds, scientists plan to use somatic cell nuclear transfer, which is the same procedure that was used to create Dolly the sheep. Somatic cell nuclear transfer begins when doctors take the egg from a donor and remove the nucleus of the egg, creating an enucleated egg. A cell, which contains DNA, is then taken from the person who is being cloned. The enucleated egg is then fused together with the cloning subject's cell using electricity. This creates an embryo, which is implanted into a surrogate mother through in vitro fertilization. If the procedure is successful, then the surrogate mother will give birth to a baby that is a clone of the cloning subject at the end of a normal gestation period. Of course, the success rate is only about one or two out of 100 embryos. It took 277 attempts to create Dolly. Take a look at the graphic below to see how the somatic cell nuclear transfer cloning process works.

Some scientists seem to think that human cloning is inevitable, but why would we want to clone people? There are many reasons that would make people turn to cloning. Let's explore a few of these reasons.

Who Will Clone?
Not all cloning would involve creating an entirely new human being. Cloning is seen as a possible way to aid some people who have severe medical problems. One potential use of cloning technology would involve creating a human repair kit. In other words, scientists could clone our cells and fix mutated genes that cause diseases. In January 2001, the British government passed rules to allow cloning of human embryos to combat diseases such as Parkinson's and Alzheimer's.

While it may take time for cloning to be fully accepted, therapeutic cloning will likely be the first step in that direction. Therapeutic cloning is the process by which a person's DNA is used to grow an embryonic clone. However, instead of inserting this embryo into a surrogate mother, its cells are used to grow stem cells. These stem cells can be used as a human repair kit. They can grow replacement organs, such as hearts, livers and skin. They can also be used to grow neurons to cure those who suffer from Alzheimer's, Parkinson's or Rett Syndrome.

Here's how therapeutic cloning works:

  • DNA is extracted from a sick person.
  • The DNA is then inserted into an enucleated donor egg.
  • The egg then divides like a typical fertilized egg and forms an embryo.
  • Stem cells are removed from the embryo.
  • Any kind of tissue or organ can be grown from these stem cells to treat the sick.

Others see cloning as a way to aid couples with infertility problems, but who want a child with at least one of the parent's biological attributes. Zavos and Antinori say that helping these couples is the goal of their research. Zavos said that there are hundreds of couples already lined to to pay approximately $50,000 for the service. The group said that the procedure would involve injecting cells from an infertile male into an egg, which would be inserted into the female's uterus. Their child would look the same as the father.

Another use for human cloning could be to bring deceased relatives back to life. Imagine using a piece of your great-grandmother's DNA to create a clone of her. In a sense, you could be the parent of your great-grandmother. This opens the door to many ethical problems, but it's a door that could soon be opened. One American couple, who has had difficulty dealing with the death of their infant daughter, is paying $500,000 to Clonaid to clone their daughter using preserved skin cells.

To Clone or Not to Clone
Critics of cloning repeat the question often associated with controversial science: "Just because we can, does it mean we should?" The closer we come to being able to clone a human, the hotter the debate over it grows. For all the good things cloning may accomplish, opponents say that it will do just as much harm. Another question is how to regulate cloning procedures.

There is no federal law banning cloning in the United States, but several states have passed their own laws to ban the practice. The U.S. Food and Drug Administration (FDA) has also said that anyone in the United States attempting human cloning must first get its permission. In Japan, human cloning is a crime that is punishable by up to 10 years in prison. England has allowed cloning human embryos, but is working to pass legislation to stop total human cloning.

While laws are one deterrent to pursuing human cloning at this time, some scientists believe the technology is not ready to be tested on humans. Ian Wilmut, one of co-creators of Dolly, has even said that human cloning projects would be criminally irresponsible. Cloning technology is still in its early stages, and nearly 98 percent of cloning efforts end in failure. The embryos are either not suitable for implanting into the uterus or they die sometime during gestation or shortly after birth.

Those clones that do survive wind up suffering from fatal or problematic genetic abnormalities. Some clones have been born with defective hearts, lung problems, diabetes, blood vessel problems and malfunctioning immune systems. One of the more famous cases was a cloned sheep that was born but suffered from chronic hyperventilation caused by malformed arteries leading to the lungs.

Opponents of cloning will point out that we can euthanize these defective clones of other animals, but they ask what happens if a human clone is born with these same problems. Advocates of cloning respond that it is now easier to pick out defective embryos even before they are implanted into the mother. The debate over human cloning is just beginning, but as science advances, it could be the biggest ethical dilemma of the 21st century.

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