title: The moral uses of 'spare' embryos.
mesh_terms: D033421:Beginning of Human Life; D033041:Embryo Research; D004624:Embryo Transfer; D004739:England; D004992:Ethics, Medical; D005307:Fertilization in Vitro / Q000379:methods*; D005615:Freezing; D005821:Genetic Techniques; D006801:Humans; D019369:Life; D009014:Morals; D028723:Personhood; D011309:Preservation, Biological; D018570:Risk Assessment