(CNN) The number of teenagers having sex is the lowest in the last 25 years and the use of condoms among teens is slightly higher than in the last 11 years, according to a new report by the Centers for Disease Control and Prevention.
However, it appears teens have not increased their use of highly effective contraceptive methods such as intrauterine devices and they continue to use withdrawal, which is one of the least effective ways to prevent pregnancy.
\"One of the goals in this report is to look at factors that influence teen childbearing,\" said Gladys M. Martinez, statistician at the CDC's National Center for Health Statistics and one of the authors of the report, which was released on Wednesday.
The researchers looked at sexual activity and contraceptive use, which are the direct determinants of whether a person gets pregnant, Martinez said. These factors are influenced in turn by other factors, such as teens' living conditions, which were not examined in the current report.