Influencing Teenagers - Advice From a Pediatrician - NYTimes.com As a pediatrician and adolescent-medicine specialist, I welcome additional evidence that the HPV vaccine has no impact on young people's sexual behavior ("An HPV Vaccine Myth Debunked," editorial, Oct. 19). This new study should reassure parents who are reluctant to let their children be vaccinated because they fear that it will be a catalyst for sexual activity. I've found that such worries distract parents from a far more significant factor in teenagers" decision-making: the parents themselves. I often remind parents that their behavior, messages and expectations play a key role in their children's decisions regarding sex and relationships; the HPV vaccine has nothing to do with it. Communicating with your son or daughter, starting in childhood, about these expectations is critical for all families. Accurate information, realistic approaches and parental support help raise a teenager who is better prepared to make healthy decisions when the time comes. The writer is a board member of Physicians for Reproductive Choice and Health.