It comes as no surprise that a British couple have used embryo screening at a clinic in Chicago to conceive a child who could act as a compatible bone marrow donor for his or her brother with leukaemia. If there are professionally approved clinics that are willing and able under the law to offer PGS (preimplantation genetic screening) for this purpose, parents will seek them out, believing that to do so is in the best interests of the family as a whole.

In addition, the ease of using the internet highlights the challenge of achieving international regulation in many aspects of medicine. The opportunity, for those who can afford it, to seek treatment abroad will be one factor that the Human Fertilisation and Embryology Authority will need to take into account in their current consideration of an application from the Hashmi family for a similar procedure here in the UK.

Preimplantation genetic testing is, rightly, a medical act, and there is an important place for international professional guidelines as part of the interdisciplinary discussions that must precede international regulation. Peer pressure in medicine and science can be a powerful influence for good in achieving some measure of international agreement. The appropriate international societies exist and such matters should be high on their agendas.