Soon after Brandon Mercer started sixth grade last year at Braintree’s Thayer Academy, he joined Facebook.
“All his friends were there,’’ said his mother, Gretchen Mercer, and she didn’t see any reason why he shouldn’t be there, too.
He was 11, two years shy of officially being allowed on Facebook. But like millions of other parents whose tweens flock to the social media site that has become a lifeblood of modern adolescence, Mercer, 49, didn’t mind breaking the rules.
“They certainly don’t make it difficult for anyone with any computer knowledge to get on,’’ she said. “Luckily he did it with my knowledge, and he didn’t get on without me knowing it.’’
It’s become one of the most pressing questions for parents of children growing up in the digital age: When should they let their children join Facebook or should they be on the site at all? An estimated 7.5 million preteens - including 5 million under 10 - are part of the social network in violation of Facebook’s terms of service, according to Consumer Reports.
A study last month funded by Microsoft Research in Cambridge found that many under-age users were aided by parents who either lied about their child’s age or were simply unaware Facebook has age limits.
According to the report, “Why parents help their children lie to Facebook about age,’’ 78 percent of parents say they would let their child join a website in violation of age requirements. When asked about Facebook’s age policy, the report found that only 53 percent of parents said they know the site has a minimum age and only half of those know it is 13.
The study calls into question the effectiveness of age limits for sites like Facebook, Twitter, YouTube, and Google, since many parents are often unaware they exist and see little problem with ignoring them.
Ambivalence about age limits has alarmed many specialists, who have created a cottage industry out of advising parents about the pitfalls of Facebook. They say unleashing young children onto a site originally created for college students opens them up to any number of grown-up scenarios - from navigating complex relationships to exposure to scams - that they often aren’t old enough to handle.
Democratic Representative Ed Markey of Massachusetts held a briefing in Washington yesterday for lawmakers and specialists on the issue of online privacy, including the topic of young children on Facebook. The social media company recently settled a Federal Trade Commission case over past privacy practices.
“Sites should take the strongest possible measures to keep kids from accessing material that isn’t appropriate,’’ said Markey. “I’m interested in giving tools to parents that make it possible for them to enhance the safety of a Wild West online world for their children.’’
The 1998 Child Online Privacy Protection Act, sponsored by Markey, forbids websites from collecting information on anyone under 13 without verifiable parental consent. The law, which is in the process of being updated, is meant to shield preteens from aggressive marketing and encourage parental involvement in their children’s online lives.
As a result, many social media sites bar anyone under 13 instead of relying on parental verification, which typically involves sending an e-mail to parents to get permission. That’s how sites such as Disney’s Club Penguin that are aimed at young children comply with privacy act requirements.
The confusion over age shows that federal policy regarding children’s online privacy isn’t working, said Danah Boyd, a researcher at Microsoft in Cambridge and lead author of the Facebook report it funded. “Nobody understands what is happening with data and privacy. We are relying on adults to make decisions about kids’ privacy when adults don’t know what they are doing.’’
Just 9 percent of parents said their child’s personal information - from who their friends are to their favorite Justin Bieber song - was being used for advertising. That suggests, according to the study, that they aren’t aware that every single thing posted online can be used for targeted ads.
“Facebook has more information and data on all of us than the FBI, and it’s because we voluntarily share that information with them,’’ said Linda Fogg Phillips, author of “Facebook for Parents.’’
The real issue with children sharing information with Facebook, she said, is that “they don’t understand the public nature of what they are saying and they don’t understand the vulnerability of being there.’’
While Facebook can be a healthy place for children to connect, say specialists and many parents, younger children in particular face a dizzying array of hazards that range from stumbling onto racy pictures to online bullying to being easier prey for scammers and hackers.
Some scammers will try to become friends with young users to extract personal details - names, birthdays, locations - as a way of figuring out their parents’ passwords. Parents often unwisely use their children’s names and birthdays as passwords whether for e-mail or online banking, said Doug Fodeman, codirector of ChildrenOnline, a Web safety consulting firm, and tech director of Brookwood School in Manchester.
Facebook is “an amazing piece of software but it’s not for younger kids, it’s not even for younger teens,’’ said Fodeman. “The critical question that no one seems to ask or care about is that just because a child can do something with technology, should they?’’
It took a year of nagging and plenty of conditions for Kimberly Jackson to let her 12 1/2-year-old daughter join Facebook.
“Whenever I would hang out with my friends they would be like, ‘I’m going to check my Facebook,’ and I would be the only person to say, ‘Oh, I don’t have a Facebook,’ ’’ said Kelly Jackson, who is now 13.
Kimberly Jackson, 50, struggled with the decision, but feeling that her daughter was mature enough to venture into social media - with guidelines like giving mom access to her Facebook page - she said OK.
“I wasn’t worried about breaking the Facebook rule because my daughter wasn’t old enough according to ‘Facebook law’,’’ she said. “I was worried about the appropriateness and the vulnerability. I worried about bullying, I worried about good judgment and knowing what to post and what not to post.’’
While some parents may see age limits as gray areas, Facebook has a more definitive view.
“The minute we know a user is underage, we immediately remove their account,’’ said Nicky Jackson Colaco, Facebook’s public policy manager. The company won’t say how many underage users it kicks off the site every year.
Jackson Colaco said the issue is difficult to police. “It’s a huge challenge for us and we are really trying to innovate and develop technology to verify the age of users,’’ she said. “There is no singular piece of technology that will keep someone under 13 from signing up.’’
About 80 percent of American teenagers who are online use social media, according to the Pew Research Center, and that means that most parents will inevitably face questions from their children about Facebook.
For Vicki Lincoln of Newburyport, whose 12-year-old son Sam has said he’d like a Facebook account, the risks outweigh the benefits.
The 51-year-old mother said it’s like putting a child in the driver’s seat of a powerful car and letting them learn by crashing. She’d rather let him play out his development highs and lows offline, and not on “such a volatile platform as Facebook.’’
Still, she acknowledged, “all we are doing is sticking our finger in the dike of an information onslaught that will be coming. We’re just trying to buy a little time to help him mature a little bit.’’