资料题：Improved medical techniques have resulted in（  ）。

When Christian Barnard, a South African doctor, performed the first human heart transplantin 1967, the result was a worldwide moral debate an the ethics of transplanting organs. Hearts were not the first human organs to be transplanted but, in this case, if a donor gave his or her heart, he or she would obviously and necessarily die (or to be dead) . Kidney transplants, which were already quite common in 1967, often involved the transfer of a single kidney from a close living relative. The chances of survival of the donor were somewhat diminished because he now had only one kidney and if that kidney were affected by disease, he would not have a healthy kidney in reserve. Nevertheless, the donor would certainly not necessarily die.Undoubtedly, another reason why the first heart transplant was so controversial was the factthat we associate so many personality traits with the heart. Questions were asked of the type:"Ifa person had a different heart, would he still be the same person?" , or“if doctors needed a dying person's heart, would they tend to declare him dead prematurely?", and so on.Since that time, surgical techniques and techniques to help prevent the patients' body systems from rejecting new organs have developed very quickly. Today, not only hearts and kidneys, but also such extremely delicate organs as lungs and livers, are transplanted. These developments have led to a far higher proportion of successful operations and this, in tum, has led to greater demand for transplants. At the same time, many of the original moral questions surrounding heart transplants have been almost forgotten.However, as a result of the heavy demand for organs, a new moral dilemma has emerged.For example, in the United States there are many people who would survive if lung were available for transplanting. In fact, about 80% of them die before a suitable donor is found. In these circumstances who would decide if a donor were found whose lungs were equally suitable for two potential recipients?This problem is made worse by the fact that many patients, or their families, become desperate to find a donor. Some succeeded in publicizing their situation in newspapers, to politicians or on television. Sometimes, as a result, suitable donors are found. But what would happen if another patient needed the organ more than the one who got the publicity? Who would decide if the other patient should get the organ? Would it be the doctors? or the donor? or the family who got the publicity? if such a dilemma developed it would be very difficult to resolve- -and it would be a matter of life or death to the patients involved.