Dawn of the saviour sibling

If you implant an 8-cell human embryo in the womb, it may or may not result in the development of a foetus and birth of a baby. If you flush the embryos left over after IVF treatment down the sink, that’s perfectly fine. But if you do anything else with them, you’re certain to generate legal problems that can turn out very differently depending on where you are, and under whose legislation you work. Laws on embryo protection are very different between countries, and often contradictory within one. The UK’s Human Fertilisation and Embryology Authority (HFEA), for instance, made the headlines in early June in two unrelated cases, whose outcomes were reported within a week of each other, by pure coincidence. In one case, the authority allowed a state-funded research institute to proceed with research that must not receive government funding in the US. In the other, a couple received treatment in the US which the HFEA had denied them. The latter case is that of the Whittaker family, whose four-yearold, Charlie, has a rare kind of anaemia. They wanted further children in any case, but in order to improve the likelihood that the new baby’s umbilical cord might help cure Charlie’s disease, they applied to the HFEA for permission to select a tissue-matched embryo. The authority had, after all, approved a similar application from the Hashmi family, who are trying to save their son Zain Hashmi from almost certain death. Unlike the Whittakers, the Hashmis had already a bunch of children (partially as a result of trying for a tissue match the natural way), so they were criticized from some quarters for trying to produce the selected baby only for Zain’s sake. The HFEA, however, did not consider the question ‘for whose sake’ a child was going to be created. Their main criterion was whether or not the proposed preimplantation diagnosis (PID) of the embryos — involving as it does the risk that the removal of one of the eight undifferentiated cells might cause problems in ways as yet unknown — served the baby to be born or whether it served only the sibling to be cured. Zain Hashmi’s disorder is genetic, so there is — in the eyes of the HFEA — a valid reason for the use of PID, to make sure the new Hashmi baby is free of Zain’s disease. And while this analysis is done anyway, the authority does not particularly mind the tissue-matching being done as well. Charlie Whittaker’s problem, however is not genetic and so, in his case, the embryo suffers the loss of a cell for reasons that only benefit Charlie, not the birth of a healthy new baby. The birth of a baby selected to be a potential stem cell donor for a sick brother pushes on the fast-developing and still contentious debate on what are the goals of stem cell research and the political boundaries that constrain its development. Michael Gross reports.