The Plain Talk initiative, developed by the Annie E. Casey Foundation, was designed to increase the amount and quality of communication that parents and community adults provided youth regarding responsible sexual decision making. It offered parents and other community adults information and skills necessary to communicate more effectively with teens about responsible sexual behavior. Plain Talk was implemented in five ethnically diverse, low income, urban neighborhoods in five states. Researchers conducted interviews and surveys that tracked changes in youths' attitudes and behaviors between 1993-98. Overall, Plain Talk changed the way adults communicated with teens about sexuality. Communication between youths and knowledgeable adults about sexuality, combined with increased access to contraceptives, positively associated with teens' sexual knowledge and behavior. Despite a long preparation time, using resident educators to spread the message ultimately enhanced sites' capacity to reach a large number of people in a relatively short time. Askable parents and askable adults played complementary roles in helping youth make responsible sexual decisions. All sites were successful in bringing new health services to their communities by forging strategic relationships with health care providers. (Contains 14 references, 12 endnotes, 12 tables, and 2 figures.) (SM)