It's confession time. I am possibly the only journalist to have written simultaneously for the News of the World and the Journal of Molecular Biology (different features, you understand). It meant that this week both the tabloid queen and the science girl bits of me were simultaneously intrigued by headlines generated by the lurid court case involving Max Mosley, the boss of FIA, the governing body of motorsport.

If you have not followed this tale, it is about an orgy and some “sadomasochistic role play” (I quote Mr Mosley's lawyer). Mr Mosley does not deny that he took part in an orgy. It was revealed that he and a nubile Mosleyette had taken turns in their role play, which was jolly sporting. Science girl here was of course thinking, what's the science here? And it's fascinating.

Theories about sadomasochism, which encompasses a spectrum of behaviours (dominance, submission, bondage) involving infliction of pain are the stuff of psychoanalysts' dreams. It was thought to be congenital, a transmuted death wish (no prizes for guessing that was Freud's theory), early childhood shaming, fear of castration and so on, ad infinitum.

But a much more probable explanation is that it is an innate sexual behaviour. Like homosexuality, it is certainly seen in animals, and many animal species bite during coitus. I'd certainly bite a two-ton male hippo if I was a lady hippo, but perhaps that's not the same thing.

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Sadomasochism is common. In his first report on sexual behaviour in 1948 Alfred Kinsey claimed that 50 per cent of respondents claimed to get erotic pleasure from being bitten, but the figure is probably nearer one in ten - and it's found equally in women and men.

A long line of research has indicated that it is higher-educated, Times-reading types who are more likely to indulge than those News of the World aficionados. I suspect a research bias here - Times readers are more likely to have the cash to spend on psychoanalysts who write research papers.

S&M behaviours can be psychological and physical. Although some people might place S&M in the same category as abuse, the important point is that it should be consensual.

There is no evidence that it leads to violent crime, although it can lead to embarrassment. A common form is to leave someone naked, defenceless and tied up. Fine if your leather-clad whip-wielding Zorro finds you. Bit of a bummer if it's the cleaning lady, your children or, worst of all, a tabloid newspaper.

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