"I wouldn't say it's quite like a superpower but I do think it's amazing that something that you just happened to be born with can help so many people."
Speaking inside the busiest blood donation centre in Europe, Julia Gryn, from Thornton Heath in south London, has popped into donate after work.
The 27-year-old is just one of about 100 donors on the NHS Blood and Transplant's (NHSBT) Rare Donor Panel. Out of about 800,000 blood donors, those on the panel make up just 0.01%.
Speaking at London's West End Donor Centre on Margaret Street, she said: "I think it's really, really amazing that I can actually help someone with a genetic disorder."
She added: "It's crazy to think that a single blood donation can help to save up to three lives."
Julia's blood is rare because she lacks several of the most common antigens across multiple blood group systems.
Of the 350 known antigens, her unique combination does not include the K, M, S, Fya and Jkb, all of which are frequently found in the general population.
Her blood type is especially important for those with sickle cell, a genetic blood disorder whereby patients develop antibodies against several blood types making it harder to find matching blood.
