It's not just parents. Schools, it turns out, can be pretty bad at it, too.
There is no state requirement that public schools teach sex ed.
That's right. Nearly half of U.S. high school students report having had sex, according to the Centers for Disease Control and Prevention, and New York State doesn't require that schools teach the subject.
And it's not like this state is lax in telling teachers what to do.
Students must learn about bicycle safety, arson prevention and the humane treatment of animals.
But, aside from mandated lessons on HIV and AIDS, they aren't required to learn about safe sex, preventing pregnancy or even abstaining from sex.
There are guidelines about what ought to be taught. But it's left entirely to school districts to decide what and how to teach the subject.
The result - according to a recent review of curriculums from schools across the state by the New York Civil Liberties Union - is a frightening mishmash of instruction that varies depending on what district your child attends.
It's not just that students in some districts aren't given all the facts. Some are given information that's outdated or medically inaccurate.
And don't expect schools to send the students home for more information. Only 43 percent explicitly encouraged students to talk to parents or trusted adults about sex or relationships, according to the study.
How do we expect teenagers to make intelligent decisions if we don't give them intelligent information?
The good news is that, in Buffalo, where the rate of teen pregnancies is higher than in Erie County as a whole, the school district is taking important first steps to understand the problem.
Buffalo Public Schools for the first time conducted a districtwide survey to find out what high school and middle school students are doing.
The survey asked students from sixth to 12th grades to report what kind of risky behaviors they had engaged in - from smoking cigarettes to drinking - but what's been catching headlines is the findings on sex.
It's not exactly news that teenagers are having sex, but there are a few disturbing details that ought to stop any parent cold:
. One out of every five high school student reported having had four or more sexual partners - 41 percent higher than across the state.
. Almost half of the middle school students who reported having had sex reported that they had had three or more partners.
The district deserves credit for attempting to understand exactly what students are doing and for putting the information out there.
But a series of public forums this month should be just the beginning. Let's face it: Community meetings are only going to draw a small number of the district's students and parents.
The district now has real numbers to understand the scope of the problem. There's no excuse for not using that data to revamp health classes and prevention programs so that students understand the risks.
It's not an issue the district can solve alone. But teachers can at least make sure students start their lives with all the facts.