On January 25, the mayor of Los Angeles signed regulation that requires the use of condoms by all performers in adult movies filmed within the city’s borders. The regulation conditions the issuance of film permits for adult movies on compliance with existing California worker safety rules, which already require barrier protection for workers exposed to blood and other potential contaminants (including semen). The ordinance spells out what these state safety rules mean in the context of the adult film industry, and requires producers to pay enough for film permits to finance workplace safety inspections.

Public health advocates have not surprisingly celebrated the regulation. Adult film producers have equally predictably been less enthusiastic, citing safe sex films as being less popular with viewers and actors alike, and threatening to move their filming elsewhere. This would not be too hard since the ordinance applies only to Los Angeles City and not to the broader Los Angeles County.

But there are other reasons the ordinance may not be as effective as one might hope.

The first is that fewer adult movies are filmed and produced professionally than was the case ten years ago. Over the past decade, free internet sites driven by home videos and other amateur content have taken over a growing slice of the porn image and film market. While it is clear that these sites are not posting free content for philanthropic reasons—indeed, online porn is said to be worth$5 billion a year—it is equally clear that the majority of US-produced porn content streamed online is not and will not be subject to filming permits.

As a corollary to this, the ordinance will not be very effective at influencing the overall depiction of sex in imagery and media. This outcome is all the more lamentable because encouraging condom use is so important. Let’s look at the facts.

Fact number one: young people in the United States act particularly clueless about the cause-and-effect links between unprotected sex, the spread of sexually transmitted infections (STIs), and unplanned pregnancies. In theUnited States, about half of the 19 million individuals newly diagnosed with an STI every year are between 15 and 24 years old. In addition, about 800,000 girls and young women between 15 and 19 years old get pregnant every year, mostly unplanned. Only about 60 percent of sexually active high school students say they used a condom during their last sexual encounter.

Fact number two: frighteningly few teenagers and pre-teens in the United States receive effective information and guidance about sex, despite the fact that 9 out of 10 kids in public secondary schools will receive some form of sex education at least once during their time from 7th to 12th grade. This is partially due to the fact that the federal government has invested several billion dollars in abstinence-only programs since 1997, including $5 million in the 2012 federal appropriations bill alone. Abstinence-only sex education teaches sexual abstinence until marriage as the only viable option for teenagers to avoid STIs and pregnancy. Under this logic, condoms are not only ineffective but also immoral because they “make” teenagers have sex. (Study after study has proven abstinence-only sex education to be ineffective at best and harmful at worst).

Fact number three: the internet is where kids go for the information they feel they need, including about sex. Successive Youth Internet Safety Surveys haveshown that children between 10 and 17 years old are increasingly exposed to sexual content on the web, and, in fact, that to a growing extent they seek this content out. This is not surprising. Teenagers will always be curious about sex, and the availability of internet viewing on portable computers and other mobile devices such as MP3 players makes it easier for them to seek out sexual content in privacy.

The scary bit is that those children and adolescents who depend on the internet for information about sex—that is, those who do not receive effective sex education at school or at home—are more likely to be influenced by what they see. Already a desk study commissioned by the US Department of Health and Human Services notes that the general effects of pornography on the viewer include more permissive sexual attitudes, including a heightened tolerance for unprotected sex.

Which brings us back to condom use in pornographic movies and imagery. We cannot really prevent children from seeking out or inadvertently being exposed to explicitly sexual content online, including from porn sites. And we cannot mandate parental support for comprehensive sex education or even just an understanding attitude towards sex. As a result, if most online porn content depicts unsafe sex as the norm, a scarily large proportion of teenagers will see it as such.

We are not, however, as powerless as the Los Angeles City ordinance. We can think of creative ways to support adult content that features safe sex—for example, government-sponsored awareness campaigns or guidelines for amateur porn, potentially supported by financial incentives. And, by mandating comprehensive age-appropriate sex education in all schools, we can make sure that no teenager will have to depend on the internet for information on sex.