03/18/2010 05:12 am ET Updated Dec 06, 2017

The 'Sex Talk': Teaching Too Late (Education Before Infection)

Even when parents make an effort to talk to their kids about sex, adolescents' sexual experience is often a step ahead of them. Apart from its emotional consequences, the health implications of this disconnect are serious, and seriously unequally distributed.

A new study in Pediatrics shows that by the time many parents talk to their children about sex, they've already had sex. The exact numbers aren't important because the sample was not representative, but more than a third of children had already had intercourse before their parents discussed many sex specifics with them: how to identity sexually transmitted disease symptoms, how to use a condom, how to choose a method of birth control, or what to do if a partner refused to use a condom (in the case of girls).

FYI, the government's National Survey of Family Growth from NSFG in 2002 found that 30% of girls have had sex at age 16, 46% at age 17, and 67% at age 18.

Given that the majority is having sex before leaving high school, you might wish that schools would provide that kind of information - which they sometimes do.

But it's not getting through to enough kids in time, as we learn from another study - this one nationally representative. It shows that, among female teenagers who reported having had sex, 38% had at least one sexually transmitted infection. The most common (30%) was human papillomavirus (HPV), which clears up harmlessly on its own in most cases. But in about 10% of cases persists, and increases the risk of cervical cancer.

(There is an HPV vaccine recommended for all girls by the federal government's advisory committee, before they have sex for the first time. But many parents and abstinence-only proponents have opposed the vaccine, and laws providing for it, on the imagined grounds that it will encourage irresponsible sexual behavior. And, because parents' rights trump children's rights, the vaccine requirements proposed in some states have a parental op-out provision.)

The study also shows the teenagers' prevalence of chlamydia (7.1%), trichomonas (3.6%), gonorrhea (2.5%), and herpes (type 2, 3.4%). Although these are curable or treatable in most cases, they do increase the risk of contracting HIV.

The lack of information or other resources necessary to protect young women's health is, not surprisingly, concentrated among poor and minority - especially African American - women. Black adolescents are about twice as likely as Whites or Mexican Americans to have any STI (44% versus 19% and 18% respectively); and those below the poverty line had almost twice the rate of those above (34% versus 19%). This is partly because these groups are more likely to have had sex or more partners, but the race difference persisted when those factors were controlled.

To overcome the problem of sexually transmitted infection, and the disparities in its distribution, will require both real sex education and health coverage that includes vaccination, screening and other services.

Cross-posted from the Family Inequality blog.