In this paper, I explore the concepts of self-realisation, health and justice as they specifically pertain to human genetic engineering. Genetic engineering is a fledgling, but rapidly developing set of technologies, whose application will have a dramatic impact upon man and his conception of himself. It is for this reason that I feel it is important that we decide whether its use will be a just or unjust practice within our society, before its envisaged applications are made available for our use on a large scale. I believe that a return to Plato's ideas on justice could serve as a valuable guide in an investigation of this contemporary conundrum. I attempt to apply Plato's nderstanding of self-realisation, health and justice to the emerging technology of genetic engineering, and come to a conclusion about the just application of this advance within contemporary society.