Sexually active male adolescents quite often have the sexually transmitted infection Chlamydia trachomatis but don’t know it. Investigators in California have found that routine urine screening for chlamydia is an effective means of diagnosing these infections in sexually active young men.In men, chlamydia can lead to inflammation of the urethra and structures of the testes. Men can pass the infection to their female sex partners whose fertility could become compromised, Dr. Kathleen P. Tebb of the University of California, San Francisco and associates note in the October issue of the American Journal of Public Health.