Screening for healthy grandchildren

A Spanish couple have used embryo sex selection to ensure their children do not inherit the altered gene that causes haemophilia, a blood clotting disorder. The case is the first published use of the technique solely to avoid conceiving healthy carriers of an inherited condition, i.e. to avoid the risk of passing on a disorder to grandchildren, rather than children. 'The couple are crazy with delight and they can now forget about haemophilia in their family' said Professor Josep Santalo, head of the team that carried out the procedure.

The father of the twin baby boys, born in May, has haemophilia, which is caused by a faulty gene on the X chromosome. This means that all his sons, who inherit their X-chromosome from their mother, will be free from haemophilia. But any of his daughters would - though healthy themselves - inherit the faulty gene, giving them a 50 per cent risk of passing the disorder on to their own sons.

The father was infected with HIV (human immunodeficiency virus) and Hepatitis C following a blood transfusion 18 years ago, so doctors first had to 'wash' his sperm to remove any virus particles. Then teams at the Universitat Autonoma de Barcelona and the Cefer Institute of Reproduction used IVF and genetic testing to ensure that only male embryos were implanted in the mother's womb.

Jack Scarisbrick, chairman of the anti-abortion group Life described the case as 'yet another step in the wrong direction'. But Professor Santalo said it was ethically acceptable. 'We are performing embryo sex selection at the embryo stage, not aborting a healthy baby at a later stage.' he added.