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.