Chicago ? Seven months after the U.S. government recommended that all preteen girls be vaccinated against the virus that causes cervical cancer, at least two dozen are struggling to decide how to make that happen.

One option would be to add the vaccine to the list of shots required for admission to school, which the governor of Texas did on Feb. 2. Proposed legislation in Illinois and 17 other states would mandate immunization; other bills would require the state to pay for the vaccine or force insurance carriers to do so.

The topic is controversial because the virus – human papillomavirus, or HPV – is sexually transmitted. Conservative groups oppose making it mandatory because they believe it encourages premarital sex.

Some other critics point out that HPV, unlike measles or chicken pox, cannot be transmitted through casual contact. Others note that the HPV vaccine is expensive – $120 for each shot in a required series of three.

Proponents agree that any mandated vaccine should be free to anyone who can’t pay. Those with good private insurance are expected to be covered, and Illinois provides free vaccines to uninsured children and those on Medicaid. But about 10 percent of children are thought to have insurance that won’t cover the vaccine.

“If we’re going to consider requiring it, the more important question is, ‘Is it so valuable that we collectively are going to put together the resources to make sure the underinsured have an equal opportunity to be protected?'” said Jerry Stermer, president of Voices for Illinois Children.

According to a recent study by the National Cancer Institute, only 40 percent of U.S. women have heard of HPV, and less than half of those were aware of the virus’ connection to cervical cancer.