  Buchanan et al. (2000) note that as technology advances, theories of justice need no longer consider “natural inequalities” to be given, or outside the scope of distribution. If equality of opportunity is one of the aims of a society, then, provision of certain forms of genetic intervention – including interventions that determine who will be brought into existence – may become owed to future people as a matter of justice. If parents can decide between implanting an embryo that carries a genetic marker associated with a serious disease –  e.g., Tay Sachs – or an embryo without that marker, they would have a moral obligation to choose the latter, in the name of promoting the health and well-being of the future child (impersonally, perhaps, given the non-identity problem).