Deaf gerbils 'hear again' after stem cell cure
12 September 2012 Last updated at 18:52 BST
UK researchers say they have taken a huge step forward in treating deafness after stem cells were used to restore hearing in animals for the first time.
Hearing partially improved when nerves in the ear, which pass sounds into the brain, were rebuilt in gerbils - a UK study in the journal Nature reports.
Getting the same improvement in people would be a shift from being unable to hear traffic to hearing a conversation.
However, treating humans is still a distant prospect.
Fergus Walsh reports.