When Christie Andrews was born, she weighed less that half of one kilogram. Her heart was the size of a large coin. Her mother said Christie was so small that she could hold her in the palm of one hand. Christie couldn't breathe without a machine to give her oxygen. If she had been born 20 years earlier, she would probably have died at once. She needed two operations, but she survived without serious damage. Twenty years ago , 90% of all premature  babies died. Today, doctors manage to save four out of every five, because they have better machines for breathing and better ways to feed the babies. But saving Christie's life cost more than $ 400,000. In some cases, doctors spend 1 million dollars saving a single child. The parents usually don't have enough money to pay. The government, an insurance company or the hospital picks up the bill. Even after a baby goes home from the hospital, it may require medical care. Some people think it makes more sense to spend money saving 10 adults who have cancer or other diseases than saving one small baby. But nobody wants to be the doctor who has to tell parents to their faces, "Sorry, I won't save your new child." The main idea of the article is  _  .
doctors must never decide whether to save babies or cancer patients doctors are able to save premature babies, but the cost is very high having a premature baby was cheaper and safer 20 years ago Christie survived because the hospital paid her bills