The health of children born after pre-implantation genetic diagnosis should be monitored for five years, says Professor Peter Braude, of King’s College London. Developed 15 years ago, PGD involves extracting a single cell from an early embryo and testing it for sex or genetic diseases. Doctors do not believe that anything is amiss with PGD children, but they lack the data to prove it.

“I don’t expect there to be abnormalities found, but there might be and I think we need to know whether this does cause any problems later. We do actually require some data to confirm that,” Professor Braude told the Guardian. He wants a European register of babies born following PGD so that their health can be monitored into their early childhood.

Professor Braude is also concerned about the growth medium for embryos. “There is no control,” he told the Telegraph. “We have more control over biscuits, crockery and cutlery than the media we grow embryos in.” Another doctor, Alan Thornhill, the scientific director of the London Fertility Centre, added that companies who develop their own culture media are allowed by the UK’s fertility regulatory authority to have “secret ingredients”. “That is not in the interest of the patient,” he said.