[单项选择]When researchers come up with a new treatment that makes us feel or work better, it’s usually not just the truly sick who end up going in for an upgrade. The progress in developing treatments for illnesses that ravage memory and thought raises an important question: might the same tools be used to improve the functioning of minds that by most standards are already running fairly smoothly We may well be approaching an era of designer brains, in which those of us feeling a little foggy or dull can have our IQ, fast recall, and self-confidence inflated up via the prescription pad. "Some brain-related conditions we think of as ordinary, "says one researcher, "may eventually become disorders, too"—including perhaps less-than-razor-sharp thinking. The notion of a prescription IQ lift is hardly new. According to polls, about one in 20 college students, and higher percentages of professors, already illicitly pop some form of Ritalin or Modafinil—legitimately prescribed for attention-de A. Breakthrough in medicine has made it possible for human to defy genetics. B. Genes have been used successfully to create brain cells. C. Gene therapies could be harmlessly employed in brain cell repairing in the future. D. The environment has a much more powerful effect on brain than genetics.