PGD involves taking a single cell from a 2-4 day old embryo and performing a genetic or chromosome test to see whether it is affected by a genetic defect. The affected embryos are then destroyed and one or two of the unaffected embryos are returned to the mother's womb.
In this case the couple want to test for CFEM. The father-to-be, and his father, both have a severe squint and can only look downwards and sideways. Although the squint varies in severity, it can cause gross abnormality in the muscles which control the gaze of the eye, resulting in severely limited vision. Using PGD, the couple can ensure that their child-to-be is not born with the debilitating condition.
The HFEA's decision to allow PGD to test for CFEM has been heavily criticised. Until now, PGD has only been used to test for more severe life-threatening conditions such as cystic fibrosis and late-onset conditions such as Huntington's disease. Critics claim CFEM is primarily a cosmetic condition and using PGD to test for it is the first step on a slippery slope to creating 'designer babies'.
Dr David King, a molecular biologist and director of Human Genetics Alert told the BBC that the HFEA have gone 'too far because the condition, despite being, admittedly, perhaps somewhat disabling doesn't shorten life in any way'.
Professor Gedis Grudzinskas, medical director of the London Bridge clinic where the procedure is due to be performed, told The Times that the condition can be emotionally distressing for those who suffer from it and that it is reasonable for parents to wish to avoid such suffering for their children.