The reasons for this are complex and worth a lengthy explanation. The Human Fertilisation and Embryology Authority (HFEA) has a policy in place which permits couples to use PGD only when it will be of benefit to the child to be born as a result of treatment. And so, couples who are at high risk of having a child with a particular inherited condition are allowed to have PGD because it allows the couple to have a healthy child. Couples using PGD for this reason may, under certain circumstances, request a further test to establish the tissue type of the embryo, thereby creating not only a healthy child, but one who could also be a tissue donor to someone else.
The Fletchers are not in this situation. Their son, Joshua, suffers from a form of Diamond Blackfan anaemia for which it is not possible to perform a genetic test. Some cases of DBA are caused by a mutation in a gene called RPS19, but for most, the trigger remains unknown. And so, the Fletchers are requesting PGD not for the purpose of ensuring that the child is free from DBA, but solely to ensure that it can be a tissue donor to Joshua. The current HFEA policy will not permit such a use of PGD because it is being performed not for the benefit of the child born, but for the benefit of the tissue donor recipient.
The Fletchers doctor, Mohammed Taranissi, says that if the HFEA turns down the Fletchers' request for treatment, he is prepared to challenge the decision in court. The HFEA is already reviewing its policy on PGD and tissue typing. In its draft business plan, the HFEA has indicated that it 'intends to conduct a review of issues raised by the selection of embryos to produce tissue donors, to be completed by the end of Autumn 2004'. But it seems that Mr Taranissi, and the couples that have sought his help, cannot wait any longer.