But one of Britain’s leading sex change doctors defended the practice, saying patients undergoing gender reassignment surgery had as much right to preserve their fertility as young people with cancer who freeze their eggs or sperm before having chemotherapy.

Dr James Barrett, of the NHS Gender Identity Clinic in West London, said three of his patients who have transitioned from women to men were close to becoming parents.

He added that, in the last year, he had asked GPs to refer about 50 of his female-to-male patients to have eggs frozen, and about 100 of his male-to-female patients to have their sperm frozen.

‘As a matter of principle, anybody who loses their fertility as a result of standard NHS treatment should be able to preserve their fertility,’ he argued.