A new report on teen pregnancy out today from the Centers for Disease Control has some scary implications for parents.

The report shows there are a lot of teen girls out there who either don’t know how babies are made or are unable to stand up to their partners and require they use contraception.

It also shows there are a slightly fewer girls who actually do know how babies are made, are using birth control or condoms and get pregnant anyway.

The study, released this week, analyzes data from the 2004 to 2008 Pregnancy Risk Assessment Monitoring System. Researchers looked at the rates of self-reported contraceptive use by girls ages 15 to 19 who became unintentionally pregnant.

According to the CDC, about half of teen girls who become unintentionally pregnant report they did not use any kind of contraception. Of those girls, nearly a third said it’s because they didn’t believe they could pregnant at the time and 23 percent said they didn’t use contraception because their partner didn’t want to. Another 22 percent said they didn’t mind getting pregnant.

Of girls who did use contraception, 21 percent reported using a highly effective contraception method such as the birth control shot, oral contraceptives or the hormonal patch, 24 percent reported using a moderately effective contraception method such as condoms and 5 percent used the least effective contraception method such as rhythm or withdrawal.

Which statistics do you find the scariest: The number of girls who didn’t think they could pregnant by having sex? Or the number of girls who reported they were using contraception when they got pregnant?