Lab-grown sperm and egg cells 'could let people of any age have children'

Scientists are just years from creating viable human reproductive cells in the lab, according to an internationally renowned pioneer of the field who says the advance could open up biology-defying possibilities.

- Hannah Devlin

Speaking to the Guardian, Prof Katsuhiko Hayashi, a developmental geneticist at the University of Osaka, said rapid progress was being made towards being able to transform adult skin or blood cells into eggs and sperm, a process known as in vitro gametogenesis (IVG).

His lab was about seven years away from the milestone, he said. Other frontrunners include a team at the University of Kyoto and the California-based startup Conception Biosciences, whose chief executive told the Guardian that growing eggs in the lab "might be the best tool we have to reverse population decline".

"I feel a bit of pressure. It feels like being in a race," said Hayashi before his talk at the European Society of Human Reproduction and Embryology's annual meeting in Paris. "On the other hand, I always try to persuade myself to keep to a scientific sense of value."

If shown to be safe, IVG could allow anyone, regardless of fertility or age, to have biological children. And given Hayashi's lab previously created mice with two biological fathers, this could possibly include same-sex couples.

"We get emails from [fertility] patients, maybe once a week," said Hayashi. "Some people say: 'I can come to Japan.' So I feel the demand from people."

Matt Krisiloff, Conception's CEO, said lab-grown eggs "could be massive in the future".