Defects in a baby's DNA are behind roughly half of cases of hearing loss in early life.
The mouse study, published in Science Translational Medicine, showed a virus could correct the genetic fault and restore some hearing.
Experts said the results could lead to treatments within a decade.
The team in the US and Switzerland focused on the tiny hairs inside the ear, which convert sounds into electrical signals that can be interpreted by the brain.
But mutations in our DNA can leave hairs unable to create the electrical signal - leaving people unable to hear.
