You've got mail and it's STD!

Health authorities in California have found a way a keeping awkward or embarrassing information on sexually transmitted disease (STD), right down to the minimum.

By using an independent email service you can let sexual partners know you have the embarrassing problem of having contacted an STD.

The service called Inspot, consists of a choice of six e-cards with messages ranging from the jokey to the sombre.

The email service tells your recent partners what the problem is and commits you to nothing, and does not even give your name if you don't wish it to.

One depicts a close-up photograph of household screws with the message: "I got screwed while screwing. You might have, too".

Another shows a suntanned, well-toned man holding a towel up to his buttocks. The caption says "You're too hot to be out of action. I got diagnosed with STD since we played. You might want to get checked, too."

The service is free and invites users to specify their diagnosis from a list ranging from minor irritation (chlamydia, crabs) to gonorrhoea, syphilis and HIV, your name and a personal message can be added if wished.

The service began on an experimental basis in San Francisco a year ago and is now, after 20,000 emails, undergoing a major expansion.

Los Angeles has unveiled its version, and Seattle, Philadelphia and Indianapolis are to follow in their footsteps in the New Year.

Public health is a precarious business but sexual health, especially in California, where the Aids epidemic took off in the 1980s, is one area where the authorities are reluctant to experiment.

Last year new diagnoses of sexually transmitted disease rose by 8 per cent among gay and bisexual men after several years of relative stability.

Experts fear that the culture of prevention surrounding HIV/Aids is weakening, while the lure of casual sex, facilitated by internet meet-up sites, is stronger than ever.

The Inspot website justifies its role with the argument that telling sexual partners about medical issues removes the stigma associated with HIV and other STDs, and is scientifically proven to reduce transmission.

However, there are concerns that the system is open to abuse and malicious users could send out postcards as a prank.

According to Inspot administrators in San Francisco fewer than 1 per cent of emails sent out since the service began there had turned out to be hoaxes.

However not everyone is a fan of Inspot, a city councilman in West Hollywood, the gay mecca of the Los Angeles region, has described the anonymous postcard route as a cowardly way to pass on vital personal information.