When the German pharmaceutical company Boehringer Ingelheim trialled flibanserin as a new anti-depressant, it was what you might call a complete flop.

But though it failed to cheer them up, it raised an unexpected smile in some females: it appeared to boost their libido. Some were even reluctant to come off the pills at the end of the trial. Assuming flibanserin receives a licence, it could be in a bedside cabinet near you by 2011, displacing all that sarsaparilla, Siberian ginseng and Chinese horny goat weed.

Contraception and the rise of feminism kindled academic interest in the once unacknowledged area of women’s desire. And, though it may have been temporarily quenched by fear of Aids, the quest for the female equivalent of Viagra has been a holy grail for drug companies since the launch of those little blue pills in 1998. It’s not hard to see why. In the very first year, Viagra produced a rather suggestive-looking spike in Pfizer’s profits.

Enter Professor John Thorp, of the University of North Carolina medical school, who announced to the world this week that flibanserin is “essentially a Viagra-like drug for women”. It depends on what you mean by “essentially”, John. You don’t need to be a professor of obstetrics to know that men and women are different. In men, sexual dysfunction relates to performance. The pills target the genital capillaries and Bob’s your uncle or, conceivably, your best friend. In men, desire is rarely an issue.

By contrast, in women, sexual dysfunction generally relates to a deficit of desire, a problem of the mind. A generation of female sexologists spent decades attempting to understand women’s arousal, without managing to answer the question posed by Sigmund Freud nearly 100 year ago: “What does a woman want?”

Browse through the work of experts such as Meredith Chivers, Marta Meana and Lisa Diamond, and what strikes you most forcibly is the lack of agreement about what turns women on. Diamond thinks there’s a strong link between intimacy and desire. Yet some women are aroused by encounters with strangers.

Meana thinks the sense of being desired is just as important. “Women want a caveman and caring,” she says, summing up what she sees as a paradox. British experts agree that female arousal is a complex subject and that different women respond to different erotic stimuli.

In other words, don’t expect flibanserin to be a “magic bullet”. It works by targeting the brain’s receptors for the pleasure-giving neurotransmitter seratonin. Judge its effectiveness for yourself. In trials on 2000 women with low libido, it raised the number of “satisfying sexual events” (SSEs) per month from 2.8 to 4.5. (I will leave you to grapple with the notion of what constitutes 0.8 of a sexual event.)

It takes several weeks to build up this drug’s effectiveness and some women experienced side-effects such as dizziness and fatigue. It has not been tried on post-menopausal women, the group with the biggest libido deficit, and only the strongest dose achieved a result.

Furthermore, the control group experienced 3.7 SSEs on nothing stronger than sugar pills. Quite aside from the subjective business of defining an SSE, in my book the unsung hero of this story is the placebo. No wonder one newspaper referred to the new drug as “fibanserin”. A Freudian slip perhaps?

There’s a much more fundamental problem about this. More number of women are being diagnosed with what is now known as “hypoactive sexual desire disorder” (protracted low libido). And you can bet we’ll be hearing a lot more about it now a “cure” is on the horizon. We’re also being told 30% of pre-menopausal women suffer from a poor sex drive.

My strong suspicion is that these numbers are being driven up by pharmaceutical companies hoping to make money. It is part of the ongoing medicalisation of conditions that were once considered part of a normal spectrum of behaviour. I’m no expert, but you only have to join the chat on a girls’ night out to know that low libido is largely the result of fractured relationships and women exhausted by cleaning, catering and caring.

Many are trying to hold down jobs as well. That’s why they fall asleep 10 seconds after getting into bed. What they need is a more understanding partner and less stress, not pills.

We should also be asking why low female libido should be regarded as a problem on an overpopulated planet when it may be simply nature’s way of telling women they do not need to reproduce. The danger is that by creating an expectation about sex, we end up convincing women who aren’t unhappy about their libido that they have a “disease” .

This disease-mongering turns individuals into patients and discourages us from taking individual action. I’m not totally cynical about the pharmaceutical industry. Conditions once dismissed as psychosomatic are now recognised as having organic causes that will respond to drugs.

As mental health conditions become treatable, the stigma that once coloured them fades. And nobody moans about the medicalisation of HIV or cancer. But drugs for pornography addiction, compulsive shopping, road rage and kleptomania?

Now there’s talk of a drug for the newly bereaved to produce “reductions in measures of grief”. Of course, unlike physiological diseases, these behavioural conditions occupy a grey area, where there is no clear boundary between “normal” and “ill”. It’s an invitation for drug companies to print money and develop ever more swanky drugs for the worried well.

What is obscene about this is that while energy, hard work and millions of research dollars go into producing “lifestyle” drugs such as flibanserin, the world’s poor are dying needlessly. Despite a groundbreaking deal at Doha in 2001 to give the world access to cheap drugs, the heavily-lobbied governments of the rich world continue to conspire with drug companies to block the developing world from obtaining them. Right now, poor countries are being prevented from producing generic versions of Tamiflu. If swine flu takes off this winter, many more will die as a result.

Comparatively little research goes into combating killers of the developing world such as malaria, while flibanserin is all set to fly off the shelves. Our answer should be No… No … No.