It is no respecter of persons: monarchs have had it, statesmen have died of it. And although it's been called ' the wages of sin', innocence doesn't guarantee protection - the sexually faithful can get it from a partner who strays even once. VD or, as it's now called, sexually transmitted disease, was on the retreat 30 years ago. It looked then as though penicillin and other drugs would banish it from our lives. But today STD is spreading again and with alarming speed, especially among the young. This year something like half-a-million cases will pass through British clinics. Doctors will treat people from every social class, not just for syphilis, gonorrhoea and NSU (the infamous three), but for more than 20 other sexually transmitted diseases, including genital herpes, the incurable virus that is already an epidemic in America. Man Alive visits the clinics where the war against the sexual diseases is being fought and Michael Dean talks to the doctors and to some of the casualties.