One might object to the substantive and level playing field conceptions of equality of opportunity canvassed so far in this entry on the ground that they all presuppose a world of individuals of given genetic makeup. Given a population of individuals each with a particular genetic makeup that fixes for that individual a profile of native talent, the question for the equal opportunity theorist is what must be done to or for such individuals if they are to be rightly regarded as enjoying equal opportunity. This framework of discussion takes for granted that native talent differentials are an unalterable natural fact. The objection is that what this framework presupposes may not be so or may eventually not be so. Advances in biological knowledge suggest that at some time in the future people can by deliberate choice alter the genetic makeup of their children or the children born in their society in order to eliminate unwanted traits and augment desired traits. The genetic influences on human traits will become subject to human control. This might occur by using genetic knowledge either to alter the genetic constitution of individuals yet to be born or to provide therapeutic interventions on already existing individuals to alter their genetic makeup. Along this line some argue that advances in genetic knowledge unsettle current moral conceptions including conceptions of equal opportunity by falsifying their factual presuppositions (Buchanan et al. 2000: chapters 3 and 7).