(CNN) -- Enter your birthdate on this site to prove that you're over 18: And please be honest, kids.
Is this the best method we can come up with for preventing children from viewing inappropriate online videos?
With the world of video on the Web reaching new audiences thanks to software like Google TV, the whole family now has access to sometimes unrated and unregulated content in the living room, just a few keystrokes away.
And a polarizing California law banning the sale of violent video games to minors is currently being heard by the U.S. Supreme Court. But seemingly little thought has been given recently to regulating how adult-themed content is presented online.
The "enter your birthdate" age-verification system is commonly employed by entertainment companies hosting mature-rated digital videos. Before viewing such a clip, the visitor is asked to input their birth day and year. Of course, the systems have no way of actually ensuring that someone enters his true age.
You'll encounter that screen before watching an episode of the profanity-laden "Louie" on FX Networks' website or before a clip for "Grand Theft Auto" on GameTrailers.com.
Two of the most popular online video sites use a variant of this. YouTube and Hulu require users to login or register an account by providing a birthdate and agreeing to their terms of service documents. (Some legal experts say these agreements wouldn't hold up in court, especially for minors.)
Last week Microsoft enhanced its Xbox Live service's age-verification system, called Family Settings. In addition to game restrictions, Xbox 360 owners can limit the types of downloaded TV shows and movies that can be watched on the system without a passcode.
Sony's PlayStation 3 has settings for restricting which mature-rated games, DVDs and Blu-rays can be played, as well as a lock for the Web browser. (Most new DVD and Blu-ray players offer similar functions.) Sony, which has sold 38 million PlayStation 3 units, doesn't appear to let owners lock content downloaded from Sony's digital store or those manually loaded onto the console.
"We're all doing something similar," Peter Dille, Sony Computer Entertainment of America's vice president of marketing, said of content controls, adding that Sony offers "extensive parental controls."
"We comply with COPA," Dille told CNN recently.
COPA stands for the Child Online Protection Act, a federal law that passed 12 years ago during President Bill Clinton's administration. The legislation provided an early framework for how violent or explicit content should be regulated on the internet.
A response to the unsuccessful Communications Decency Act, COPA would require commercial websites containing material "harmful to minors" to restrict kids from accessing their sites. What constitutes "harmful" isn't entirely clear.
But COPA has been challenged throughout its history for alleged First Amendment violations. Last year the U.S. Supreme Court refused to hear appeals, effectively killing the bill.
"To say they [Sony] are complying with COPA is a nonsensical statement," said James Schmidt, one of 15 members on the long-disbanded COPA Commission.
That's because the commission determined that there was no technological means to protect minors online, said Schmidt, a retired professor at San Jose State University. That opinion even took into account the birthdate-input mechanisms in use today.
"The commission's conclusion was that age verification schemes were so patently transparent that they were of no use," Schmidt said. "How long will it take a 13-year-old to figure that out?"
"It's silly," he added. "It's just plain silly."
Like movies, video games are packaged with age-appropriate ratings. A rating of M (Mature) means the game contains content -- language, blood and gore, sexual situations -- that may not be suitable for people younger than 17. Titles rated AO (Adults Only) contain even more graphic content and are intended for gamers 18 and older.
These ratings are determined by Entertainment Software Rating Board, a non-profit that assesses which age groups are suitable audiences for video games. The board promotes a variation of the birthdate system, which it calls "age gates."
These screening tools, displayed before a user can access a video rated Mature or Adults Only, don't specifically say why the site is asking for a birthdate. The idea is to deter children from lying in order to see a video.
The ESRB also asks websites to install a tracking device in a visitor's Web browser to prevent that person from pressing the "back" button and changing their birthdate after being denied access. The board says it will regularly audit sites to ensure that they're complying.
"They hadn't been doing it particularly consistently or up to the standards that the industry has adopted," ESRB President Patricia Vance said of video-game websites. "The internet is an exceedingly difficult medium to regulate. And I think [this rule] is a very responsible approach to that issue."
GameTrailers.com has refused to install a tracking device in browsers. That's in order to protect adults who accidentally enter the wrong birthdate and get locked out, said Shane Satterfield, the site's editor in chief. GameTrailers.com has had an age gate in place since 2006, he said.
"The ESRB wanted to make the barrier a little more extreme than we had wanted to," Satterfield said. "We can't police the internet to make sure they [users] are telling the truth. We can't check their IDs."
Some entertainment sites worry that getting too fancy with age verification mechanisms could frustrate legitimate consumers.
For example, SouthParkStudios.com, which streams full episodes of the irreverent Comedy Central show "South Park," forgoes age verification altogether.
Movie studios are testing systems that require more information, such as the viewer's name, and then checks the entry against government databases.
Representatives for YouTube, Sony, FX Networks and South Park Studios (a subsidiary of MTV Networks Entertainment Group, which also operates GameTrailers.com) didn't return requests for comment. Hulu and a Fox executive declined to comment.
"We can't prevent kids from lying about their age," the ESRB's Vance said. "The important part is that we aren't inappropriately marketing these games to children."
Satterfield said the responsibility of educating children on what types of content are OK to watch lies with the parents. It's a common argument among advocates against proposed legislation to regulate how stores can sell kids violent video games -- such as the current Supreme Court case.
"If you've raised the kid right and your kid knows right from wrong, then your kid does know what an age gate is and that they shouldn't be there," Satterfield said. If sites "put the red flags in place," he said, then kids might think twice about watching things they aren't supposed to.
The COPA Commission, when tasked with recommending online protections more than a decade ago, came to a similar conclusion.
"We believed first and foremost that the responsibility for monitoring access to content on the internet lies with parents and legal guardians," Schmidt said.