A new study from the University of Southern California set out to determine the prevalence of the relatively rare condition known as phonagnosia. This disorder, which most people likely have never even heard of, describes the inability to recognize the voices of those close to you. According to the research, approximately 3% of people can’t recognize voices, and they may not even know it. 
For the research, 730 participants were asked to identify the voices of celebrities whose work they were familiar with. Twenty-three people, or 3.2%, were demonstrated to have trouble or be unable to do the task at hand. Scientists were astounded by the number, having only expected around 8 or so people to fail at recognition.
In a follow up survey, researchers asked the 23 who were unable to identify celebrity voices if they were able to imagine what these famous people sound like, or if they were able to remember what friends or family sound like. Eighteen of them said they were unable to do so, though some were able to identify certain characteristics. For instance, one participant stated that she knew Morgan Freeman had a deep voice, but she had a hard time imagining what it sounded like. 
But while these individuals had trouble recognizing and imagining voices, they were able to imagine things like what birds singing sounds like or the noise dogs make when they bark.
Within the research group itself, 76% of people were able to recognize celebrity voices with very little trouble. They also noted that older people tended to perform better on the test than their younger counterparts, coming to the conclusion that people are likely born with the condition.
The inability to recognize voices is slightly similar to prosopagnosia, the inability to recognize faces. However, researchers have found that the 2 conditions do not seem to overlap. Many people with prosopagnosia have acquired it after a trauma, while those with phonagnosia have had the condition since birth. 
 IFL Science
 Huffington Post
 The Independent