Pharmaceutical companies GlaxoSmithKline and Merck are competing to get regulatory approval for vaccines that protect against the sexually transmitted disease human papillomavirus -- the leading cause of cervical cancer -- but they also must contend with groups that oppose the widespread vaccination of preteens and children, the Philadelphia Inquirer reports. Because many people contract the virus the first time they have sexual intercourse, the companies emphasize that the vaccines must be given before sexual debut to be effective (Vrazo, Philadelphia Inquirer, 7/4). Merck -- which makes Gardasil -- said it might lobby states to require the vaccine for all 12-year-old children before they can enter school, and GSK -- which manufactures Cervarix -- plans to recommend its HPV vaccine for girls as young as age 10. However, some parents and health officials object to standardized vaccinations for teenagers and are concerned that children would interpret them as permission to have sex (Kaiser Daily Reproductive Health Report, 5/20). "If a 10- or 12-year-old is given a vaccine to protect against sexually transmitted disease, then it's implied they'd be engaging in risky sexual behavior," Pia de Solenni of the Family Research Council said. However, Dayle Steinberg, president of Planned Parenthood of Southeastern Pennsylvania, said it is "ludicrous" to think that teenagers are abstaining from sex because they are concerned about developing cervical cancer later in life. Merck plans to seek FDA approval for Gardasil this year and, if approved, introduce the vaccine in the United States in 2006. GSK plans first to apply for European regulatory approval for Cervarix, which it hopes to receive by 2007, but the company has not announced a timeline for its U.S. application for FDA approval (Philadelphia Inquirer, 7/4). By age 50, 80% of U.S. women have contracted at least one type of HPV (Vollmer, Raleigh News & Observer, 7/3). About 250,000 women worldwide die annually from cervical cancer, and the American Cancer Society estimates that about 3,700 women die of the disease each year in the United States (Kaiser Daily Reproductive Health Report, 5/20).