[单选题]23.Cloning, a Controversial Issue
AA new life begins when a male sperm a female egg join. This new life has in it some chromosomes from the father some from the mother. So it will inherit some characteristics from each parent. It is, if you like, a mix of both parents. Everyone knows this is true of all human life.
B But here comes the shock. Now, we are told, human life can start in another way. A way that does not need to join a male sperm a female egg. This new way of reproduction is called cloning.
C This is how it works. Each single cell in the human body has in it a full set of chromosomes. All the genetic information that a living thing needs is in those chromosomes in the nucleus of the cell. So if any body cell can be made to divide grow, it can form a new life. Since this new life would have only one set of chromosomes, it would be an exact replica of the body it comes from. This type of cloning has worked with plants, fruit flies, even frogs.
D As far back as 1968 a man, J.B. Gurdon from Oxford University, produced a cloned frog.
E Could this procedure work with people? Scientists say it could. it would work in much the same way. A healthy egg would be taken from a woman's body. No male sperm would fertilize it. The nucleus of the egg would be destroyed. It would be replaced with the nucleus of a new cell taken from the arm or anywhere else on the body of the donor. This donor could be a man or woman. The egg would then be put back into the womb of the woman. The egg would grow into a new life even though no sperm had fertilized it.
F The new baby would have only one parent. The parent would not have to be the woman in whose womb it grew. The parent would be the donor from whom the new nucleus had come, because it would be that person's chromosomes in the new baby. the baby would be an exact twin of the donor.
G Cloning means that anyone could have a child. It would give new hope to people who cannot have a baby in the usual way. All you have to do is have one cell taken from anywhere on your body. Then, the nucleus of that cell would be put in the place of the nucleus of an egg cell allowed to grow in a womb, or perhaps in a test tube. A new life would be made that would be a twin of the donor.
H Scientists are still at work to see if they can make this new way of reproduction perfect.
I But the thought of cloning brings all sorts of questions fears. The use of cloning could change our world to the point where we might not know it. The family, as it is now, would not exist. Sex would not be needed for reproduction. The whole meaning of "parent" would change. We might even end up with whole tribes of people who look exactly alike. "Clone clans" might take the place of nations races.
J It is easy to see how cloning could be misused. One nation could set out to make a race of cruel "Hitlers" who would all be exactly alike who would kill or make slaves of everyone else in the world.
K What about crime? Think what would happen if all the murderers, thieves, cheats, swindlers in the world made thousands of clones of themselves to run the greatest crime ring in the history of the world.
L What about things that go wrong? What if - by accident - we got a race of hideous monsters that would make clones of themselves forever ruin the world? Scientists cannot promise that such things might not happen.
M There is also the moral side of the issue. Is it right for humans to change the way life begins? Or is God the only one who can do that?
N Of course, there is a bright side. Think of all the great people in the world who could clone themselves so their genius could last forever. The world could keep all its great athletes, writers, engineers, scientists, scholars. There could be a constant supply of all the good useful people the world could need.
O There are many things to consider about clones. But the fact remains. Whether you think it is right or wrong, it can be done. It has already been done with animals. Is there any reason why it should not be tried with humans?
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Q23.1 A naturally born baby can not be an exact replica of either of its parents because____.
R A. the baby develops its own set of chromosomes
S B. the baby takes one cell from each parent
T C. genetic information can not be inherited from either parent
U D. chromosomes from both parents mix to form the new life of the baby
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