A new vaccine aimed at halting the spread of a common sexually transmitted virus that can lead to cervical cancer should eventually be given to both sexes, doctors said on Monday.

The vaccine, Merck & Co. Inc.‘s Gardasil, was licensed in June by the U.S. Food and Drug Administration for use in women and girls 9 to 26 years of age.

It protects against four types of the human papillomavirus, also known as HPV or human wart virus.

A government advisory committee agreed a month ago to recommend the vaccine for girls aged 11 and 12, girls and women aged 13 to 26 who have not yet received the vaccine and women who have had abnormal pap smears, genital warts or certain other conditions.

Dr. Bradley Monk, associate professor in gynecologic oncology at the University of California at Irvine, said the best use of the vaccine would include giving it to girls and boys and all women and men, regardless of their individual risk factors.

“We need to move toward a paradigm where this is a universal vaccine,” he said in a commentary published in the latest issue of the journal Obstetrics & Gynecology.

But some groups oppose requiring the shots for school attendance, saying parents should decide whether to immunize their children against a sexually transmitted virus.

Men can pass on the virus to their sexual partners, so it makes sense to vaccinate boys against HPV, and it would also protect them from genital warts, Monk said.

He dismissed the argument that vaccinating people against a sexually transmitted disease would encourage promiscuity.

“Just because you wear a seat belt, does that mean you drive recklessly? Or just because you give your son a tetanus shot, does that mean he is going to go out and step on a rusty nail? Of course not,” Monk said.

GlaxoSmithKline Plc is also developing a vaccine against HPV strains, which infect about half of sexually active adults sometime during their life.

The virus is usually harmless, but can lead to abnormal cells in the cervix lining that can turn cancerous. It can also cause cancer of the penis.

“To have a vaccine that prevents cancer and not use it would be one of the greatest tragedies,” Monk said.