In 2001, the American Academy of Pediatrics announced that the typical American teenager views nearly 14,000 sexual references every year. Think that’s a lot? The number might have increased by now.

“The amount of sexual material [in the media] increased dramatically over the last 15 years,” Shirley Feldman, Stanford’s Associate Director of the Program in Human Biology, said. “A majority of American youth becomes sexually active by 17, so it’s no longer seen as atypical or deviant behavior—that’s not to say everyone is comfortable with this.”

While most people have accepted the reality of the sex-saturated media, on-screen sex used to be the kind of thing that could permanently destroy a directing career. The first major on-screen kiss came in 1926 with the movie “Flesh and the Devil,” a silent film about childhood friends who wind up becoming soldiers. Television was even stricter: even in the 1950s, the most sexual act depicted was kissing, and many married television couples had separate beds.

Starting in the 1930s, the Motion Picture Association of America’s (MPAA) created the Production Code, a set of guidelines for what is morally acceptable in American films. The Code restricted movies for decades; however, the sexual liberation of the 1960s prompted the MPAA to toss the code in favor of a rating system. We’ve come a long way: according to the Kaiser Family Foundation, by 2001, movies had an 87 percent chance of presenting sexual material.

But teenage sex—and sex in general—remains a very gray area for many Americans. “[The media-made] American society is more ‘schizophrenic’ about sex,” Stanford Sociology Professor Paula England wrote in an e-mail. “On the one hand, we are surrounded with explicit sexual material, while on the other hand, sex education programs in high school must teach the dangers of sex and the imperfections of contraception.” In many cases, schools and media sources give teens conflicting messages about birth control.

According to the Kaiser Family Foundation, 64 percent of all television shows include sexual content, but only 15 percent mention waiting, protection and consequences. England believes that depicting more contraception on-screen might change off-screen attitudes. “It might make people feel that sex can still be passionate even if you stop to worry about safety,” she wrote. “Now, the media seems to think it is just un-sexy to have to worry about it.”

The expanding pornography industry also presents problems. Since the Internet’s debut, pornography became more accessible to both adults and minors (incriminating magazines or video store trips can now be easily bypassed). But England notes that pornography’s wide distribution may have negative effects on men’s perception of women—and sex in general. “A lot of pornography, for example, shows women being raped and dominated,” England wrote. “Some studies show that the pairing of sexual arousal with such violence increases men’s callousness and tendency to think that if a woman is raped, she probably deserved it.” Still, there are two sides to every coin. “Feminists have argued about whether [pornography] is freeing for women (and men of course), or whether it has increased the acceptance of an attitude of objectification and exploitation of women,” England wrote. “It is complicated—it is probably some of each.”

Whichever direction sexual content in the media takes next—more protection, more youth or even more kink—we can be almost certain of one thing: it isn’t going anywhere anytime soon. “I think the media is likely to increase references and portrayals of sexuality,” Feldman said. “I can’t see any reason why there will be less depiction of sex—sex sells.”