1. Which of these statements gives the best summary of the text?
a. Human cloning is technically possible but it will never be attempted.
b. The prospect of a human clone is so dizzying that attempt to clone a human being would be quite possible.
c. A donor and a clone would be no more alike than two identical twins.
2. Which approach to human cloning do you think the author prefer?
a. Despite the fact that cloning today remains a largely experimental procedure that often results in animals that have serious physical defects, scientists will carry it out.
b. Human cloning is impossible because scientists are no different than average citizens in their aversion to this idea.
c. The author thinks the answer to the question if anyone would actually attempt to clone a human being is still open.
TEXT 2
Human Cloning
1. Reproductive cloning may interest scientists because of its potential to yield products such as medicines, but it has captured the attention of the average person because it raises the possibility of human cloning. Despite some grandiose claims to the contrary, we have no reason to believe that a human being has ever been cloned so far. But this does not mean that the feat is technically impossible or that it will never be attempted.
2. The prospect of a human clone is so dizzying that it’s worthwhile to think about what such a person would represent in biological terms. He or she would be a genetic replica of the person who provided the donor cell with the DNA in it. One helpful way to think of this person’s biological status is in terms of a more familiar concept: that of an identical twin. As it happens, identical twins also are genetic replicas of one another. Early in a human pregnancy, separate cells from a single embryo can start forming as two separate embryos, and the result is identical twins. Cloning is a different means of producing genetically identical individuals, but the critical point is that a donor and a clone would be no more alike than two identical twins.
3. The parallels between twins and clones end there, however, because the donor-DNA cell for a clone can come from so many different sources. It could, for example, come from a person of any age an 80-year-old, an 8-year-old; it could even come from a fetus. Indeed, the donor cell used in cloning need not even come from a living person. In 2001, an American couple sought help in cloning their son, who had died in a hospital operation at the age 10 months. How could this boy be cloned? Through the use of cells that were taken from him while he was alive and then frozen. It was these cells that the parents proposed to use as the donor-DNA cells in cloning the boy (which was never attempted).
4. Given possibilities such as these, the prospect of a human clone has the power to stun us generally to repulse us, to judge by news reports. And scientists are no different than average citizens in their aversion to the idea of human cloning. But does this mean that no scientist in the world would be willing to undertake the procedure? Actually, several have already announced that they are willing to carry it out, despite the fact that cloning today remains a largely experimental procedure that often results in animals that have serious physical defects.
5. Newborn clones often display respiratory distress and circulatory problems, the most common causes of neonatal death. Even apparently healthy survivors may suffer from immune dysfunction, or kidney or brain malformation, which can contribute to death later.
6. With possibilities such as these in mind, would anyone actually attempt to clone a human being? Only time will tell.
(David Krogh. Biology: a guide to the natural world. - Pearson Education, 2011)
