In an article recently published in this journal, I raised a puzzle about the control of genetic information, suggesting a situation in which it might turn out that we have a duty to remain in ignorance about at least some aspects of our own genome. In this article, I propose a way that would make sense of how the puzzle arises, and offer a way to resolve it and similar puzzles in future: in essence, we would consider genetic information to be something the distribution of which may be more or less just. We would not know in advance what a just distribution would be, though, and in some cases there might still be a justice-based reason to deny a person genetic information about himself. However, others might also have justice-based claims to be able to access that information. This suggests that there is a possible world in which one person is entitled to at least some genetic information about another, while that other person—to whom the information refers—is not, and that this world would be just.