Which is more effective--abstinence only education or comprehensive sex ed?

Which does the best job reducing teen pregnancies and STDs?Which is more effective--abstinence only education or comprehensive sex ed?
Recent studies seem to indicate that abstinence-only sex education doesn't actually prevent kids from having sex; on average, teens who pledge to remain virgins do so only for about four to five months longer than those who have comprehensive sex education. In terms of teen pregnancies and STD's, comprehensive sex education completely has abstinence-only beat- in countries where comprehensive sex education is taught, the numbers are always lower.
I know that it's conterintuitive, but we've got to start seeing that abstinence-only sex education, for all its talk, simply can't deliver. It doesn't do what it says it can.
I definitely suggest you read Judith Levine's book "Harmful to Minors: The Perils of Protecting Our Children From Sex", which discusses various studies which have shown the failures of abstinence-only sex education.
Hope that helps!
Quote of the day:
"Abstinence-only sex education is a little bit like just-hold-it potty training." -Roy Zimmerman.
Abstinence only isn't education; it's propaganda. Just judging by the questions in Men's & Women's Health on YA there is a serious need for comprehensive sex-ed.
personally, i think they should do a little of both. explain why waiting would be a good idea but they have to teach the sex ed for those that are going to have sex so they know how to protect themselves.
abstinence only has been proven to be completely ineffective