Ethical campaigners have attacked the decision to allow a British couple to use IVF to create a "designer baby" whose cells could cure their son.
The move was a "dangerous precedent" that could be commercially exploited across the globe, said Dr Anthony Cole, acting chairman of the Medical Ethics Alliance.
The Human Fertilisation and Embryology Authority (HFEA) yesterday ruled that Shahana and Raj Hashmi, from Moortown, Leeds, could use pre-implantation genetic diagnosis (PGD) to "create" a baby whose cells could then be used to cure their son, Zain, who suffers from a rare blood disease.
But as the decision sparked controversy last night, The Independent on Sunday established that more than 50 women are pregnant with so-called designer babies, conceived to help cure an older sibling with a life-threatening disease.
The American university that pioneered the approach said yesterday that a number of women had now been implanted with embryos selected as matches for an older child with any one of a number of genetic conditions.
"There are about 50 women at various stages of their pregnancy, and there are a handful, maybe about five, from the UK," said Sarah Youngerman of Minnesota University. "In all cases there are older children who have one of a number of different types of conditions. In total, we have had more than 500 inquires from America and elsewhere.''
Yesterday, the Bishop of Oxford, said that the practice of designer babies should be done on a case-by-case basis.
"I think a very clear distinction can be made between preventing disease on the one hand and enhancing ordinary qualities on the other, and we wouldn't want to stray from the one to the other," the Right Reverend Richard Harris said. "It's very important in this case that the child is wanted for his or her own sake But it's surely morally legitimate that the benefits which their birth brings should also be used."
Adam Nash made history almost two years by becoming the world's first designer baby. He was conceived and his embryo selected so that he could help save the life of his six-year-old sister, Molly, who desperately needed a bone marrow transplant.
"Clearly there are a number of ethical issues," said Dr John Wagner, clinical director at Minnesota University's stem cell centre, who led work on that first case.
"One of the goals has been to make people aware that embryo research can be very positive and that our motivation is pure."
Join our new commenting forum
Join thought-provoking conversations, follow other Independent readers and see their replies