We are never told directly who the child is or how it comes to be imprisoned and tortured. In fact, the child’s identity is so eroded that it “could be a boy or a girl.” The story gives us clues, though, about why the child suffers as it does, which helps readers speculate as to who it might be. Forming such interpretations allows us to understand how ambiguity about the child’s origins emphasizes the negative characteristics of the townspeople who keep the child captured, increasing the story’s horror.
First, we must consider the location where the child is imprisoned. We are told that it is “in a basement under one of the beautiful public buildings of Omelas, or perhaps in the cellar of one of its spacious private homes …” An uncertain location further reinforces the child’s unknown identity. If it is below a public building, then it may be an orphan or a child kidnapped from another town. If it is below a large private residence, then it is likely the child of the home's occupants. Either way, we know that everybody in the village is aware of the child, which means the town’s entire population can be regarded as either accomplices to kidnapping or domestic abuse.
The child is immediately described as having lower intelligence, and the story suggests that “perhaps it was born defective …” What exactly do the villager’s consider “defective”? If the child were described as dangerous, that would seem to provide more justification for imprisonment; instead, the word “defective” makes the villagers seem unwilling to help people that have problems. If the child had low intelligence, then perhaps they thought that it would be less bothered by mistreatment. Or perhaps, using rather flawed logic, they thought imprisonment would protect it from the world. Such a thought may make the villagers seem well-intentioned, but that hardly excuses their terrible treatment of the child.
We are also told that “perhaps it has become imbecile through fear, malnutrition, and neglect,” which seems a more likely possibility since we are later told that the child “has not always lived in the tool room, and can remember sunlight and its mother’s voice …” Being capable of remembering its early life shows that the child has not always been confined, which makes a birth defect less likely. The child also pleads for clemency, saying, “‘I will be good,’ it says. ‘Please let me out. I will be good!’” The child is intelligent enough to speak the language and to bargain, so all of this evidence indicates that whoever the child is, it is likely normal. Thus, the child’s degrading mental state results from the villagers' poor treatment of it, which makes them seem all the more horrible.
While we never know exactly who the Omelas child is, that ambiguous identity actually reveals the many cruelties of the people who keep it captured. Since the entire story focuses on how the villagers (and readers) cope with knowledge of the child, it seems likely that the child’s lack of a clear identity is a way to further emphasize the story’s moral dilemma.