Although the HPV vaccine is approved for girls starting at 9 years old, a new study indicates many U.S. mothers aren't inclined to give the shot to girls that young.

The HPV vaccine, marketed as Gardasil, protects against the human papilloma virus, which can cause cervical cancer.

The CDC recommends girls get the vaccine before they become sexually active, as experts say HPV is often acquired soon after.

While 86% of surveyed moms said they intended to vaccinate their 16 to 18-year old daughters, just 48% they would have their 9 to 12-year olds get the shot.