Despite often-heard concerns about the prevalence and recklessness of teen sex, the teen birth rate in the United States is at an all-time low.

According to a CNN report, “The teenage birth rate in the United States has fallen to a record low in the seven decades since such statistics were last collected. A report released Tuesday by the National Center for Health Statistics showed the teenage birth rate for American teenagers fell 9 percent from 2009 to 2010. The national level, 34.3 teenage births per 1,000 women between the ages of 15 and 19, is the lowest since 1946. The rates dropped across all racial and ethnic groups, and nearly all states.”

NEWS: Teens Today vs. 1982

Causes of the decline are complex but researchers say the main factor is an increase in contraceptive use, along with an overall drop in sexual activity among teens and the delaying of sexual activity by them. Some also credit the recession (people tend to choose to have fewer babies in hard economic times), though it seems unlikely that the majority of teen pregnancies (often unplanned) were deterred by the tough economy.

To many people this statistic comes as a surprise, in part because it contradicts conventional wisdom and alarmist parental concerns about sexually active kids. According to many media critics, our culture is awash in unhealthy media messages of promiscuity. People — and especially teens — are highly influenced by media, they claim, and that media often sends toxic, sexualized messages that encourage sex and unhealthy behaviors. A few years ago it was scandalous, panty-less photos of Britney Spears; then there was widespread concern over teen sexting; and then came casual-sex-friendly “reality” TV shows like Jersey Shore. And so on.

Surely all the sex-saturated airwaves are having an effect on kids, right? Many pundits and parents believe that all this sexualized content is leading otherwise chaste teens into more — and riskier — sex at earlier and earlier ages.

Those fears seem to have been largely unfounded; just because kids, teens and adults see trashy and slutty behavior on TV doesn’t mean that they’re copying it in their real lives. (In fact a report last year from the Girl Scout Research Institute found that regular reality TV viewers are more confident and self-assured than nonviewers, suggesting that there may be benefits to reality TV.)

NEWS: Teens Brains Linked to Pop Song’s Success

There is of course a long history of concern over media influences on kids, from childrens’ books to Hollywood thrillers. While no one doubts that advertising and pop culture have some influence, all the sex teens are exposed to on TV, on the Internet, in suggestive song lyrics and elsewhere doesn’t seem to translate into real-life sex. And, like the plummeting teen birth rates, that’s good news for everyone.