A、It still remains in an experimental stage at present. B、It has taken the place of surgery or medicine. C、It has only been trie

"We used to think that our fate was in our stars, but now we know that, to a large extent, our fate is in our genes," said James Watson, a gene biologist. Scientists are seeing that gene therapy is reforming the treatment of disease.
    Although much of the research is at the beginning stages, some successes point to the real benefit of the therapy. In Italy, doctors have recently treated one genetic disease with gene therapy. This disease most often begins to destroy the brain when children are between 1 and 2, stopping them from walking and talking. By inserting normal, healthy genetic material into a virus and then infecting the patients, scientists seem to be able to cure the disease. The children given the therapy are now in kindergarten and living normal lives.
    Gene therapy has also been used to help older patients. These people suffer from a disease that causes slow movement and uncontrollable shaking because part of the brain dies. Those treated with gene therapy showed a 23. 1 percent improvement when tested six months later.
    Gene therapy appears to be a more positive alternative to surgery or medicine. But more research is needed to assure its safety.
Questions 13 to 15 are based on the passage you have just heard.
13. How do scientists use gene therapy to treat children with brain disease?
14. Which of the following statements about gene therapy is true?
15. What is the speaker mainly talking about?