This prospective study describes the epidemiology of adult sexually transmitted disease agents in 1538 children ages 1 to 12 years being evaluated for possible sexual abuse. Infections with these agents were related to the presence or absence of a history of sexual contact. Neisseria gonorrhoeae (GC) was found in 2.8% (41 of 1469); human papillomavirus presenting as condyloma acuminata, 1.8%; Chlamydia trachomatis, 1.2% (17 of 1473); Treponema pallidum (syphilis), 0.1% (1 of 1263); and herpes simplex virus, 0.1%. Overall a history of sexual contact was present in 83% of children with N. gonorrhoeae; condyloma acuminata, 43%; Chlamydia trachomatis, 94%; syphilis, 0%; and herpes simplex virus, 50%. Selected vaginal discharges were examined for Trichomonas vaginalis and bacterial vaginosis. In children comprehending questions regarding sexual contact (i.e. were "verbal"), 89% with N. gonorrhoeae, 100% with Chlamydia trachomatis and 63% with condyloma acuminata had a history of sexual contact, indicating that in "verbal" children any infection with N. gonorrhoeae or C. trachomatis was highly associated with sexual contact.