Fertility doctors have extracted eggs from girls as young as five and frozen them so they can be used later to start a family. The breakthrough raises hopes for thousands of girls who survive childhood cancer each year but are left infertile by chemotherapy.

Until now, fertility specialists had thought it impossible to retrieve usable eggs from girls so young, but a team of Israeli doctors managed to extract early-stage eggs and mature them in a laboratory before storing them in deep freeze.

As cancer in children is often diagnosed late it can be far more advanced than in adults and require more aggressive treatment. Progress in childhood cancer therapy has seen cure rates rise substantially, but the chemotherapy tends to leave females infertile.