Demi-Lee Brennan, a nine-year-old girl in Sydney, waited for a liver transplant for five years. When a mismatched organ - from a donor with a different blood group - became available, her doctors chanced it; after all, a heavily medicated life would be better than no life.

In fact, Demi-Lee, now 15, has made history by becoming the first person to have spontaneously switched blood type after an organ transplant. Before the operation she was O-negative. Afterwards, she became O-positive, the blood type of the donor. Scientists think that the stem cells in the donated liver overwhelmed her bone marrow, where blood cells are produced, and started mass-producing O-positive blood.

It was not a painless process: the battle for supremacy between Demi-Lee's own blood cells and the proliferating donor ones brought her close to death. But within a few months of doctors withdrawing her anti-rejection medicines - basically, waving a white flag to the invading blood cells - the changeover was complete. She is now flourishing.

Her case was revealed in the New England Journal of Medicine, and scientists are trying to work out why it happened. One suggestion is that the combination of the donor being young - a 12-year-old boy who died after a brain injury - a post-op infection and Demi-Lee's low white blood cell count, probably triggered the one-in-six-billion occurrence. Whatever the explanation, researchers believe that Demi-Lee's story could make a life-saving contribution to understanding organ rejection.

— An e-mail drops from the Spiked blog, teasingly entitled “liberal writer ‘witch-hunted' by environmentalists”. Alexander Cockburn, a columnist on The Nation, fumes: “For daring to [question the consensus on human-induced climate change] I have been treated as if I have committed intellectual blasphemy... I think people have had enough of peer-reviewed science and experts telling them what they can and cannot think and say about climate change.”

Cockburn is an Eng Lit graduate who for his articles on global warming sought input from Dr Martin Hertzberg, who describes himself as “an internationally recognised expert on combustion, flames, explosions, and fire research with over 100 publications in those areas”. So he is an expert on warming, but not in the way you might expect.

That Cockburn should set himself up as some kind of hounded Galileo figure is laughable. But the status of victim is popular among the dwindling numbers of climate-change deniers, largely because they cannot fall back on the comfort of facts. That's because the facts, as best we know them, come courtesy of the peer-reviewed science that Cockburn so despises. Everything else is opinion.

I do believe that everyone should be free to express their opinion, no matter how bonkers. You can proclaim that the Sun goes round the Earth and garlic cures Aids.

But that don't make it so.

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