Several recent studies looked at how many teens have sex, how often, and why.
The big question for parents of course is what can they do about it.
When it comes to teenagers and sex, the latest studies say there are two constants.
First, many teens are having sex. And second, many parents are not talking to them about sex.
"MY PARENTS NEVER SAT ME DOWN AND TALKED TO ME ABOUT IT OR ANYTHING."
"NO, I THINK MY PARENTS MIGHT BE AFRAID TO TALK ABOUT SEX WITH ME."
One study says one in five teenagers is having sex before their 15th birthday, and that only one third of parents of sexually active children know their kids are having sex.
Dr. Brenda Wade/ Psychologist: "THERE IS NO PROTECTION IN IGNORANCE."
Psychologist Dr. Brenda Wade says parents have to talk to their kids about sex, and those conversations have to start before the children become sexually active.
DR. BRENDA WADE: "IT IS A FACT THAT CHILDREN WHO ARE MORE INFORMED MAKE BETTER CHOICES. IT IS THE UNINFORMED CHILDREN WHO MAKE THE WORST CHOICES."
Dr. Wade says those conversations should begin when the child is ten or 11, and they have to be explicit and open.
Many teens themselves recognize the importance of honesty, particularly when it comes to something as important as sex.
Megan Voss/ Student: "I THINK IT'S VERY IMPORTANT FOR STUDENTS TO BE AWARE OF EVERYTHING THAT IS OUT THERE. AND I DON'T THINK STUDENTS SHOULD BE SHELTERED FROM ANYTHING."
Experts say by trying to shelter children from sex, all parents are doing is leaving them unprotected and exposing them to life-long problems, from unwanted pregnancy to sexually transmitted diseases.
One in five teenage girls have an unrecognized sexually transmitted disease-- chlamydia, hpv, or gonorhea.
What's more, half of all cases of hiv are contracted before the age of 24.
The studies noted that boys, as well as girls, feel increasingly pressured to have sex, and that drugs and alcohol often lead to unsafe sex.