The company is now testing ways to allow those kids to participate without needing to lie. This would likely be under parental supervision, such as by connecting children's accounts to their parents' accounts.
Like many other online services, Facebook prohibits kids under 13 because federal law requires companies to obtain parental consent if they want to collect information about those children.
Such information collection is central to Facebook. Every photo or status update a kid posts on Facebook could count as information collection. Many companies consider the parental-consent requirement too burdensome, so they simply ban all children under 13 instead.
But that ban is difficult to enforce. In many cases, parents themselves help children skirt it by setting up profiles for them and lying about their ages. There are an estimated 7.5 million kids under 13 on Facebook, out of more than 900 million users worldwide.
In a statement, Facebook noted that many recent reports have highlighted "just how difficult it is to enforce age restrictions on the Internet, especially when parents want their children to access online content and services."
"We are in continuous dialogue with stakeholders, regulators and other policymakers about how best to help parents keep their kids safe in an evolving online environment," the company said.
Few details are available on the nature of Facebook's tests, which The Wall Street Journal reported on in Monday's editions. Relaxing the ban on younger children could be a long way off, or never get implemented, as happens with many features that Facebook tests.
The report comes just two weeks after Facebook began trading stock as a public company. Its stock price has fallen in part because of concerns about its ability to keep increasing revenue and make money from its growing mobile audience.
To James Steyer, the CEO of the non-profit Common Sense Media, Facebook's discussions on permitting young kids to join is about expanding its audience — and profits.
"With the growing concerns and pressure around Facebook's business model, the company appears to be doing whatever it takes to identify new revenue streams and short-term corporate profits to impress spooked shareholders," Steyer said in a statement.
But Stephen Balkan, the CEO of another kids-and-technology non-profit, the Family Online Safety Institute, disagrees.
Balkan, who sits on Facebook's Safety Advisory Board in an unpaid position, said the company has been discussing the issue for more than a year. That's months before Facebook made regulatory filings in February for its initial public offering of stock, which took place in mid-May.
"It has nothing to do with the IPO," he said.
Balkan offered some ideas about what Facebook could look like for kids. For one, the default setting to their account could be set to "friends only" so that strangers can't see their posts. Teenagers who are 13 to 17 currently have their accounts set to "friends of friends" by default, so the under-13 restriction would be a step beyond that.
In addition, parents could have final say on whom their kids become friends with on Facebook. And Facebook could even keep advertising off kids' accounts, he added.
"I wouldn't be surprised if we see some movement from Facebook this before the end of the year," Balkan said. "By the way I think it would be a good thing if they do it right, rather than this untenable situation of just kicking off under-13s when they discover them."