If you are young, unmarried and enjoy an active love life (say two or more partners during the past 12 months) there is a fair chance you have or get a sexually-transmitted infection (STI).

The national sex survey cancelled by Margaret Thatcher in the mid-80s did continue, thanks to the Wellcome Trust and its latest sweep shows that one in 10 men and one in eight women have had an STI. Genital warts, urethritis and chlamydia (which men also get and pass on) are the most common. Random screening of urine samples also shows a "significant burden of undiagnosed chlamydial infection in the population"*.

More women are having more sex; the chart shows they are now more like men in the number of partners they have. Diaphragms and condoms are barriers to infection as well as sperm but while use of the latter has grown somewhat, the former belongs to yesterday. The result is a higher risk of infection. Cases of gonorrhoea are at their highest for a decade. Attendances at hospital clinics offering a genito-urinary service (GUM) have doubled since 1990. The year 2000 saw the largest number of newly-diagnosed HIV infections yet.

HIV aside, STIs do not generally kill. But chlamydia can lead to pelvic inflammatory disease and infertility - and the cost of trying to undo that later is huge. The fact is that there is a lot of disease out there. Try this analogy. What if a normal activity, shaking hands say, led to debilitating infection? There would of course be an outcry and spending boom. Before long someone would also say that the obvious remedy is to wear gloves. And with that weak joke you see one reason why a clear-cut strategy for sexual health, published last year by the Department of Health, is languishing in do nothing land.

We're British; sex is not deemed to be "normal" in the hand-shaking sense. Because sex is such a trigger for moralists, sexual health gets short shrift. Stop them doing it, cries the Melanie Phillips tendency. Sex is embarrassing. Lads, some of them apparently now in the very highest corridors of power, only snigger.

Yet last year more than a million people attended genito-urinary clinics. Into obscure Mortimer Market, where University College Hospital has its clinic, have even strayed senior politicians and their partners. But sexual hygiene is a subject that dare not speak its name. Yvette Cooper, the minister responsible, is primarily concerned with avoiding giving offence.

The strategy on which she has signed off allocates £47.5m over two years. Yet nearly half of England's GUM clinics cannot see urgent cases within 24 hours and three-quarters have to turn patients away. There is an annual gap between capacity and demand estimated at 100,000 patients. Clinics need modernising and doctors need training: there would need to be 93% more consultants to get to the guideline figure of one per 113,000 population.

But any more of that and it starts to look like shroud-waving conveniently timed for the comprehensive spending review, which is now hotting up. There is a good case for more money and better clinics; sexual disease afflicts the young and their existing "share" of health provision is probably unfair, though the reverse applies to their share of money for education.

But the real argument here is about health spending further up the line, before people need to turn up at clinics. It is about how active the state should be in informing and persuading people about their most intimate behaviour. That's the trouble with sex. Some ministers just don't like drawing attention to it. While he was still at education, David Blunkett fought hard to tone down the strategy.

No one is saying Alan Milburn or Yvette Cooper are pro-family prudish. It is more that the former is fixated on waiting lists. The public's health in the widest sense matters far less than the headlines. Blairite ministers have neither the time nor intellectual energy to tell the public that spending on the NHS and "health" are hard to relate.

Ms Cooper does not want to sound nannyish and perhaps her political instincts are right. Advocacy of any particular way of behaving by politicians is likely to produce its opposite. (Perhaps, then, if she were to argue for wild, universal, unprotected sex, condom use would rocket.)

Behind this lies a deeper problem, which has nothing to do with morality and everything to do with the capacity of modern governments. After the MMR fuss, the medical establishment is despondent. Liam Donaldson, the chief medical officer, felt he had an ethical responsibility to hold stoutly to the pro-MMR line. But, aided and abetted by the newspapers, the public are indulging in a mood of know-nothingism. All messages from the state appear tainted.

The Cabinet Office performance and innovation unit is about to publish a big study of risk, asking how government can persuade people of objective truths, let alone the probabilities they need in order to make wise judgments of their own. With sex objectivity is especially difficult.

The Dutch are so much better than the British in cutting teenage pregnancy because schools here have a boy-dominated classroom culture that just cannot handle objective information. Jokes from the lads, cowardly ministers and changes of lifestyle (especially by women) add up to more business for the underfunded GUM clinics.
*Lancet 2001: 358;