A great deal has been written on the ethical aspects of saviour siblings, with views largely converging on similar basic position: easy case saviour siblings are permissible and hard cases are not. The important distinction to draw here is between the reasons for having a child and the treatment of the resulting child. Saviour siblings are children whose tissue or organs will be donated so that a brother or sister will be saved. The treatment of existing saviour siblings immediately involves ethical questions about live organ donation by children. This chapter suggests that the appropriate standards for live organ donation by children should be adopted to decide the acceptability of the use of preimplantation genetic diagnosis (PGD) for saviour siblings. This amounts not to an ethical judgement about the procreative reasons of prospective parents; instead, it is a practical judgement based on the permissibility of particular ways of treating children.

This chapter discusses the consensus views obtained from the 57th Study Group on various aspects of reproductive genetics. It emphasizes that fetal karyotyping should remain the gold standard test following invasive prenatal diagnosis until appropriately tested and evaluated higher-resolution whole-genome analytical methods can be introduced. Preimplantation genetic diagnosis (PGD) for saviour siblings should be permitted or denied based on the permissibility or impermissibility of live-organ donation by children. Focused basic research is needed to understand the normal genetic and epigenetic events that occur during primordial germ cell specification from embryonic stem (ES) cells and in the differentiation of primordial germ cells. Improvements in vector design and safety will be needed before safe targeted delivery to the fetus can be achieved; studies into long-term safety in large animal models (non-human primates) should be supported. Research is needed into the long-term outcomes of novel therapeutic interventions.