Freddie and Thomas Greenstreet's parents both carry genes that made it highly likely their children would be born with cystic fibrosis, a debilitating, inherited condition from which their daughter suffers. So their mother Catherine decided to have her embryos screened and to be implanted only with those that were healthy.
Mrs Greenstreet, 38, defended her decision to reject the imperfect embryos, saying she and husband Jim, 41, did not want to repeat the experience of caring for a seriously ill child.
"Unless you have lived with a child that has a terrible disability or disease then you can't speak about it. Who can criticise you for trying to get rid of horrible diseases? They are designer babies but they are designed for the good of mankind."
Mrs Greenstreet, a physiotherapist, and her husband, who works in corporate finance, already have five-year-old twins, William and Lizzie. Lizzie has cystic fibrosis, which causes severe respiratory problems and limits life expectancy. William has not got the disease but may be carrying the faulty genes. But having witnessed Lizzie's struggles, the Greenstreets, from Chiswick, decided to go for genetic screening at Guy's Hospital where their embryos could be screened for up to 6,000 conditions.
First, Mrs Greenstreet had embryos created through in-vitro fertilisation. Then a single cell was taken from each embryo and tested for the faulty genes. Only healthy embryos were chosen and implanted into her womb. Freddie and Thomas, who were born on 30 October, are the first babies in the UK to be delivered after use of this particular method and the 100th birth since the screening programme at Guy's was set up.
Alison Lashwood, a consultant nurse in genetics, said: "It is fantastic to have helped so many couples who were carrying genes for serious genetic disorders to have the babies they thought they could never have. We are very proud of this achievement and, as one of the biggest and most advanced centres in Europe, we hope we can help many more couples in the future."
November 2006 | 
Market Research, Parents and Babies
