What, when, and how should kids learn about sex? The answers to those questions vary greatly from family to family and school to school across the country. But, a coalition of teachers, sexuality educators, public health advocates, and medical experts says it's time to set some standards when it comes to sex ed. Here, a brief guide:

What are these educators proposing?
A group of sexuality education advocates and 40 experts in health education, sexuality education, public health, public policy, philanthropy, and advocacy have created what they are calling "The National Sexuality Education Standards: Core Content and Skills, K-12." Their purpose, says the National Education Association Health Information Network's Executive Director, Jerry Newberry, is to provide educators with a guide to "the minimum they need to teach to set students on a path to sexual health and responsible adulthood." And they say schools should begin the process in second grade.

What standards do they set?
For starters, they say second graders should know and be able to explain that all living beings reproduce, and know the correct terms for all body parts. Then, by the time a student finishes the fifth grade, he should understand how puberty readies the body for reproduction, have knowledge of how HIV can be transmitted, and know what constitutes sexual harassment and abuse. Eighth grade graduates should know about emergency contraception, understand the idea of gender roles, and have received some abstinence education. High school graduates should be capable of describing, step-by-step, how to use a condom.

What standards are currently in place?
None. On average, a students receives about 17 hours of sexual health education prior to college — three hours in grade school, six in middle school, and eight in high school, according to the Centers for Disease Control. "There is not, and probably never will be, a real national sexual education policy (unless you count our years of financing only abstinence-based programs)," says K.J. Dell'Antonia in The New York Times. The real purpose of this proposal is to spur discussion as to what kids should know about sex at different age levels.

Is the idea proving controversial?
Not surprisingly, yes. The executive director of the National Abstinence Education Association, Valerie Huber, doesn't think such standards should be in place. "Controversial topics are best reserved for conversations between parent and child, not in the classroom," she says. I disagree, says Dell'Antonia. "I'm unconvinced by some of [the] hard lines" in this proposal, but the U.S. has one of the highest rates of teen pregnancy in the industrialized world, so "I want sex education in the classroom, and plenty of it." It's important to start early with age-appropriate guidelines like these, says Cora Collette Breuner, a member of the American Academy of Pediatrics committee on adolescence. "Kids have already formulated their own opinions and biases by the time they're in middle and high school," she says. At that point, "it's too late" to start talking about this stuff.

Sources: Associated Press, Everyday Health, NY Times, Sexuality Education and Information Council of the United States