Despite the advent of CRISPR, safe and effective gene editing for human enhancement remains well beyond our current technological capabilities. For the discussion about enhancing human beings to be worth having, then, we must assume that gene-editing technology will improve rapidly. However, rapid progress in the development and application of any technology comes at a price: obsolescence. If the genetic enhancements we can provide children get better and better each year, then the enhancements granted to children born in any given year will rapidly go out of date. Sooner or later, every modified child will find him- or herself to be “yesterday’s child.” The impacts of such obsolescence on our individual, social, and philosophical self-understanding constitute an underexplored set of considerations relevant to the ethics of genome editing.