Efforts to prevent heterosexual transmission of HIV (human immunodeficiency virus) infection have thus far focused on modifying sexual behaviors and the use of condoms. While the experience of family planners, particularly in those countries most threatened by heterosexual HIV transmission, has shown that the most effective measures of pregnancy prevention have relied on women, little attention has been given to barriers to HIV transmission that depend on the woman and are under her control. Tactics which interrupt transmission of the virus should be considered in their own right and separated from those that interrupt pregnancy, for insurance, the diaphragm. Greater emphasis is urged for research on preventive methods women could use, including the possibility of a topical virucide that might block transmission through the vaginal route.