Some of the world's most famous singers have had problems with their vocal cords. You might remember that Adele, whose song "Hello" this month became the fastest-selling digital download ever, had vocal cord surgery four years ago.
The singer and actress Julie Andrews has had multiple surgeries to repair vocal cords that were damaged in the 1990s during a routine surgery. These are well-known cases of vocal cord problems, but it's an issue that affects millions of people.
In fact, an estimated 20 million people in the United States have vocal cord damage. Vocal cords can get damaged from cysts, surgeries, cancers and other ailments. Often, people come out of surgery with a hoarseness in their voice that doesn't go away. Other people lose their voice entirely.
There's an exciting medical breakthrough that can someday help these people. Scientists at the University of Wisconsin have grown 170 vocal cords from cells collected from people.