Abstract: This article examines the rational project of Plato pertaining to upbringing of children in the ideal state. The discovered by Ancient Greeks rational style of reasoning, creates a tough and reduced to the essential grounds picture of the upbringing process. Rationalism explains its thorough explication and scrupulous analysis of smallest details of the upbringing activity. These two qualities are also a response of the philosophical reason for its realization in culture. In its history, philosophical reason confessedly oriented at rational principles, often led to utopian social projects. Plato is the first to build social utopia, when his ideas state becomes a rational idea, hardly adjusted (or not adjusted whatsoever) to be realized in real life. Thus, Plato alongside the Italian thinker T. Campanella, viewed childbirth as a task that requires solution at the state level. He found it reasonable to join best men with best women for the purpose of improvement of the gene pool and reproduction of the “exceptional offsprings”. At the same time, only its best part was subject to upbringing; infanticide and abortions were not being condemned.