The dramatic declines in teenage pregnancy rates noted in the United States between 1995 and 2002 were largely due to improved contraceptive use, not to abstinence, a new study shows.

The article goes into far more detail but I just want to point out that this is evidence that teens can and do make responsible choices when choosing to be sexually active. Indeed, contraceptive use accounted for 86% of the drop whereas abstinence can only claim 14%.