One small in vitro study has suggested that the human immunodeficiency virus (HIV) cannot pass through latex, synthetic skin, or natural skin condoms, despite the use of higher virus levels than those found in human semen. Spermicidically lubricated condoms may be more effective than plain condoms in preventing HIV transmission. Nine studies among both men and women have shown a protective effect of condoms against bacterial sexually transmitted diseases, and one study has shown a slightly lower rate of herpes among condom users. A small number of studies among prostitutes and among uninfected sexual partners of AIDS patients indicate evidence of condom prophylaxis related to HIV. Epidemiologic studies of the effect of spermicide use on viral sexually transmitted diseases do not yet exist. The use of condoms is unlikely to be harmful with respect to HIV transmission, but the potential for harm exists if their use is substituted for for abstinence, monogamy, or good judgment. Clinical trials are needed to evaluate the effectiveness of different barrier methods as well as nonbarrier methods. 20 references.