Approximately 85% of American women (52 million) between the ages of 15 and 44 are sexually active . Approximately two-thirds or 38 million women use some form of birth control and/or STD prevention. With growing awareness of the risk of STDs, increasing numbers of women will require contraceptive methods that provide protection against STDs in addition to providing the basic contraceptive function. Currently there is no single, reasonably effective method to achieve both ends. Condoms, both male and female, present problems of acceptability for the partners of many at-risk women and, thus, cannot be considered an effective contraceptive and STD preventive for many people. A spermicide that also has the ability to prevent transmission of STDs would be a major advance, and of tremendous value to women worldwide.