INDIANAPOLIS (AP) — Religious conservatives are objecting to an Indiana State Department of Health letter sent to parents who have not vaccinated their children from a virus that can cause cervical cancer.

The Fort Wayne Journal Gazette reports that Micah Clark, of the American Family Association of Indiana, sent an email to supporters objecting to the state letter that went out to 305,000 parents. Clark called the letter intrusive and balked at the idea of a state vaccine database keeping track of children.

The vaccination prevents the most common types of the human papilloma virus, a sexually transmitted virus that can cause cancer and genital warts. Indiana ranks 40th in the country with about 23 percent of girls ages 13-16 having received all three doses of the HPV vaccine.