The makers of the controversial HPV vaccine are trying to crack a new market for their product—boys. Gardasil, protects women against human papillomavirus, a common sexually transmitted infection, that can lead to cervical cancer. But vaccination programs for young girls came under fire from religious and parents’ groups who claimed the shots might encourage promiscuity. Now, Merck & Co, the manufacturer, has asked the U.S. FDA to approve Gardasil for males aged 9 to 26. Studies suggest the vaccine would protect boys against genital warts and less common cancers, as well as protecting their sexual partners.