The next time you take your adolescent or teenaged daughter in for a physical exam, the pediatrician may ask if you have heard about the new vaccine to help prevent cervical cancer.

Parents should be prepared to ask questions about the immunizations and to answer their daughters' questions as well.

Approved in June 2006, the vaccination is approved to immunize girls and young women against four strains of the genital human papillomavirus (HPV), which cause 70 percent of cervical cancers and 90 percent of genital warts. The cervix is the lower section of the uterus that leads into the vagina.

HPV is contracted through sexual intercourse or skin-to-skin contact of infected areas. In most cases, the virus causes no harm. However, the virus can infect healthy cells in the cervix, causing them to grow abnormal precancerous lesions. If left untreated, those lesions can develop into cervical cancer, which kills about 3,800 women a year, according to the American Cancer Society.

The HPV vaccinations are administered as a series of three shots over a six-month period. They are recommended for 11- and 12- year-old girls and may be given to girls as young as 9 and to women up to age 26. The vaccine may be controversial because recipients are adolescent girls and HPV is a sexually transmitted disease. However, the vaccine is most effective at preventing HPV if it is given before a girl is exposed to HPV, which means before she is sexually active.

After sexual activity begins, there is increased risk of HPV infection and the vaccine may not work as well if the virus is already present. According to the Centers for Disease Control and Prevention, about 6.2 million people are infected each year with HPV. Most of them are men and women in their late teens and early 20s. Thus far, the HPV vaccine is not approved for boys or men.

Some parents have balked at the idea of adding yet another vaccination to the list of childhood immunizations already administered to children. The vaccine does not contain any live virus. Side effects of the vaccination include soreness at the injection site and some reports of fainting. Some states have introduced or passed legislation to make the vaccine mandatory for school, although parents can sign a waiver if they do not want their daughters to have it.

Even with the vaccine, women still need regular Pap screening tests for cervical cancer. The vaccine protects against the most common HPV strains, but other strains may also cause cervical cancer. Pap tests are recommended beginning three years after a girl or woman becomes sexually active and no later than age 21.