One of the most preposterous arguments raised by religious and social conservatives against administering a vaccine to girls to protect them from human papillomavirus, or HPV, has been that it might encourage them to become promiscuous. That notion has now been thoroughly repudiated by a study published on Monday in Pediatrics, a journal of the American Academy of Pediatrics.

Although most women infected with HPV, the most common sexually transmitted virus, experience no symptoms, persistent infections with some strains of the virus can cause cervical and other types of cancer, as well as genital warts. In 2006, the government’s top committee of experts on immunization practices recommended that all girls ages 11 or 12, and even some as young as 9, receive the vaccine so that they could develop immunity before they became sexually active. The Centers for Disease Control and Prevention, the American Academy of Pediatrics, the American Cancer Society and the American Academy of Family Physicians have all endorsed the recommendations and attest to the vaccine’s safety.

In previous surveys, teenage girls have said they would not modify their sexual behavior after getting the HPV vaccine, but those were based on self-reporting which is not considered highly reliable. The new study, conducted by researchers from Kaiser Permanente and Emory University, analyzed medical data collected by the Kaiser Permanente managed care plan in metropolitan Atlanta. It looked at 1,400 girls who were 11 or 12 in 2006, roughly a third of whom had received the HPV vaccine, and followed them for up to three years.

Over all, there was no difference between girls who had received the vaccine and those who had not in such indicators of sexual activity as pregnancies, sexually transmitted diseases, testing for sexually transmitted diseases and counseling on how to use contraceptives. As one expert said, parents should think of the vaccine as they would a bicycle helmet; it is protection, not an invitation to risky behavior.