PSAs spur dads to urge kids to delay sex 6 (UPI) -- Public service announcements, part of the Parents Speak Up National Campaign, encourage U.S. fathers to talk to their kids about delaying sex, researchers say. Lead author Jonathan L. Blitstein, a research psychologist at RTI International and colleagues at George Washington University, tracked changes in parent-child communication habits following exposure to public health messages over an 18-month period. More than 1,200 U.S. parents of adolescent or pre-adolescent children were exposed to video, print and audio PSAs, which promoted the benefits of parents speaking to their children about delaying the initiation of sexual activity. A control group of almost 700 parents were not exposed to the messages. The study, published in The American Journal of Health Promotion, found fathers exposed to the PSAs demonstrated a consistent and increasing pattern of father-child communication over the 18-month period compared with fathers not exposed to the PSAs. However, among mothers, the PSAs had little lasting impact, Blitstein said. "With this study, we wanted to extend our understanding of the impact of health-related PSA campaigns on parent-child communication patterns and explore these communication patterns as a developmental process over an extended period of time," Blitstein said in a statement. We found that mothers and fathers respond differently to these messages and that may be due to the fact that mothers in general are more likely to talk to their children about sensitive topics, such as sexual behavior.