Sexual Health.
Britain is in the grip of an epidemic of sexually transmitted infections. The number of cases of gonorrhoea has doubled in the last five years and the number of confirmed syphilis cases has risen tenfold. But chlamydia remains the most worrying disease: as many as one in ten men and women under under the age of 25 now carry it, and it's a major cause of female infertility. Most will have no symptoms and remain unaware that they, or their partners, have a problem. Dr Mark Porter investigates. Repeated from yesterday at 9pm