On July 21 2004, the Human Fertilisation and Embryology Authority (HFEA), Britain’s regulatory agency for reproductive technologies, revised its policy on preimplantation genetic diagnosis (PGD) for tissue typing.^1,2 The authority of the HFEA to enact such a policy was affirmed by the UK’s highest court, the House of Lords, on April 28 2005.³ Preimplantation genetic diagnosis combines in vitro fertilisation (IVF) with genetic testing. In PGD, embryos generally undergo biopsy prior to the eight cell stage, followed by genetic testing for a particular trait. Tissue typing PGD is done to identify an embryo that is tissue matched for a child (a future sibling) suffering from a severe disease requiring bone marrow or cord blood stem cell transplantation and for whom no living donor exists. This procedure was first performed in 2000.⁴ Precise matching of tissue types is critical to successful tissue transplant, and the donors of such tissues are often referred to as “saviour siblings”.

Where a tissue matched individual already exists, extracting bone marrow from that individual or collecting cord blood already in storage, rather than creating a match, presents the most immediate treatment alternative. Bone marrow donation from adults or other medically competent individuals is not generally ethically contested, and bone marrow donation from medically incompetent individuals (including children) is also permissible under certain conditions.⁵ Where no living tissue donor exists, however, intentionally creating a donor through tissue typing PGD is among a short list of possible treatment options.

The July HFEA policy change makes PGD licensable in cases where tissue typing is the only purpose of testing. Previously, PGD was licensable in the UK only for disease testing, and tissue typing PGD was permissible only when …