Deafness is common in the dalmatian dog breed. Not only are a sizable percentage born deaf, but among those that can hear, many of them (roughly 22%) have unilateral hearing. That means they can only hear through one ear, which makes it harder for them to tell where sounds are coming from.
Organizations like the Dalmatian Club of America advocate putting down deaf dalmatian pups with the hopes that this will, in the future, eliminate dalmatian deafness. Many people object to this practice. While deaf dogs can be hard to raise and keep safe, it turns out that they can still be trained. They can even learn sign language!
Here's the DCA's position on destroying deaf dalmatians. They also have more about unilateral hearing and the genetics behind dalmatian deafness.