Early human beings had sex with Neanderthals. Sex! It grabs the attention so easily, that story. So easily that even biologists believed it for a while. Now, though, they are trying to rein themselves in a bit.

This story, which first broke a couple of years ago, was based on an analysis of the Neanderthal genome. It produced some interesting facts. Some Neanderthals had ginger hair. Some were lactose-intolerant. And, most exciting of all, some of their genes live on in modern non-Europeans. The whole costly, time-consuming effort to sequence the genome had paid off. Our ancestors had sex with the Neanderthals. Sex! Sex with our evolutionary cousins! Hardly a newspaper across the world failed to carry the story.

Hardly any of them reported the small print, though. The disclaimer was that, being evolutionary cousins, our two species share a common ancestor, and so they could have common genes for that terribly dull reason. Now a paper published by the US National Academy of Sciences has poured further cold water on the sex-between-species hypothesis. Its analysis of the genetics says there is no evidence that the Neanderthals, who lived in Europe, were seduced by the early human beings who moved out of North Africa. The scandal is off.

Yet there is hope (and let’s face it, we want it to be true). New technology can tell us how recently a gene evolved. It turns out that the shared genes almost certainly emerged after the Neanderthals first came on to the scene. They cannot be from a common ancestor. The research hasn’t been published yet, so a little caution would be becoming, but it seems we can soon get back to being the result of humans and Neanderthals having sex. Sex!

We do like stories about sex. Ideally, they will be about illicit practices or deviations from whatever constitutes the norm. Hence the success of the Fifty Shades series. Hence the success of certain newspapers (“Five Times A Night!”). It gives us a context in which we can gauge our own contribution.

We could wring our hands about our unreconstructed nature but sex is at the centre of human thought, and always has been. Some of the earliest cave art has erotic themes. We didn’t get where we are without genetic programming that makes us value eating, drinking and having sex.

Add to that our inbuilt compulsion to tell stories and draw lessons from them, and you have a heady mix. When science investigates matters of sex, the discoveries don’t belong to science for long. From female fruit bats that perform fellatio on their partners to same-sex couplings in the Laysan albatross, science’s discoveries are powerful. That is because we can bend the scientific facts to our own ends.

Cheap tricks

The Sunday Times once heralded a study of sheep neurobiology as something that “could pave the way for breeding out homosexuality in humans”. New Scientist has occasionally gone for reader entrapment, writing up a paper titled Female-Limited Polymorphism in the Copulatory Organ of a Traumatically Inseminating Insect as “Bat bugs turn transsexual to avoid stabbing penises”. It’s a cheap trick, but it gets a click.

Those two examples are not chosen at random – they come from a paper published in Nature this month. In it, two biologists offer cautionary advice to scientists researching sexual behaviour in the animal kingdom: if you talk to journalists in terms that might remotely be applied to human beings, be sure that that is how they will be applied. There’s no such thing as a lesbian albatross, but when you pit science against sex there can be only one winner. Sex!

Michael Brooks’s “The Secret Anarchy of Science” is published by Profile Books (£8.99).