Teenagers need medically accurate, up-to-date and impartial information about the physical and emotional consequences of sex. They should hear that abstinence is the safest and best approach, but they should know details about contraception and how to most effectively prevent pregnancy and sexually transmitted infections.

Arizona is one of the few states that requires parents to opt-in for their students for sex ed at school, instead of it being part of the regular curriculum that parents can pull their students out of, should they wish. They can also keep their children out of instruction about HIV/AIDS — a disease that, while treatments have vastly improved, is still deadly.

Reporting by Caitlin Schmidt, a journalism apprentice at the Star, found that few Tucson-

area public school students are enrolled in sex education classes this year.

Three districts — Tucson Unified, Catalina Foothills and Sunnyside — offer the education but don’t keep track of how many students sign up. Of the five other districts that do, fewer than 25 percent of students were enrolled, public records showed. And the Marana Unified School District, which has 12,000 students in its schools, offers no sex education at all.

Sexuality can be framed in religion, spirituality and morality – conversations that belong within a family. But the mechanics are biological and every individual should know how the human body works and how to take care of themselves.

Not having formal sex education classes isn’t keeping students from becoming sexually active. The 2013 Youth Risk Behavior Survey of Arizona high schools found that 30 percent of respondents 15 or younger stated they had had sexual intercourse. Among students 18 and younger it’s 61 percent.

The majority of high school seniors have had sexual intercourse. Most 18-and-older students report having one or two partners, but 10 percent of them say they’ve had sexual intercourse with six or more people.

Most high school students report that they don’t always use condoms — only 27 percent stated that they had used a condom the most recent time they’d had sex. Nearly 6 percent said they used the withdrawal method (which is effective about one-quarter of the time) to prevent pregnancy, and 1.5 percent stated they were “not sure.”

Parents should be the primary educators about sexuality, but, and let’s be honest, it’s a difficult conversation, and it can be awkward. Contraceptives have changed and there are many more options than just a few years ago. Lines of communication should be open, but there’s a lot of important and detailed sensitive information to cover.

State Rep. Victoria Steele, D-Tucson, co-sponsored legislation in this session that would have had parents opt their students out of sex education, instead of having to seek out the classes, but the bill went nowhere. The measure should come back and deserves a hearing.

Knowledge isn’t a license to have sex, but a lack of knowledge is not prevention.