Facebook is considering ways to invite children younger than 13 onto its social network, a controversial move that could bolster the company’s bottom line but also spark concern among regulators over the safety of young Internet users.

The move highlights what analysts say will be a recurring problem for the newly public firm: Facebook needs to find ways to increase revenue and please its shareholders, but those actions can stir privacy concerns.

And few subjects have sparked as much debate as the social networking giant’s interaction with young children. Kids are spending more time online than ever. On social networks, they are exposing themselves with pictures, location information and details about their personal lives — all valuable information for advertisers who want to hawk sodas and jeans or ingrain their brand names on young minds.

So far, Facebook has restricted users younger than 13.

“They have so many problems with privacy and the impact of social media on the social, cognitive and emotional development of teens. Why on the earth would I want them to also go after my 8- or 9-year-old?” said Jim Steyer, chief executive of the child advocacy group Common Sense Media. “What’s next, Facebook for toddlers?”

Facebook said it hasn’t made any final decisions on its plans for children, but it points to what it describes as a problem: Millions of underage kids are on its site already. A report funded by Microsoft recently showed that parents are often helping their children set up Facebook accounts.

The company said it does its best to remove underage users once they are identified by age verification technology or by alerts from other users. But many youths get through those filters, and the company is considering whether it is better to let children create Facebook pages and simply do a better job of monitoring their safety.

“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,” Facebook spokesman Andrew Noyes said.

But critics say that opening Facebook to pre-teens because they are already on it is akin to lifting the minimum age restrictions on buying liquor.

Some lawmakers panned any attempts by Facebook to change its age policy.

Reps. Edward J. Markey (D-Mass.) and Joe Barton (R-Tex.) sent a letter Monday to Facebook chief executive Mark Zuckerberg warning against moves that would expose children on the Internet.

“We acknowledge that more and more children under the age of 13 are using Facebook, and this is a problem that needs to be addressed,” Markey and Barton wrote in their letter. “However, we believe strongly that children and their personal information should not be viewed as a commodity to be bought and sold to the highest bidder.”

One of Facebook’s biggest critics, Sen. John D. Rockefeller IV (D-Wa.) said in November: “I am not a great fan of Facebook,” because the site has led to cyber-bullying and other intense social pressures. Too often, children expose themselves unknowingly to the public, he said.

The possible change to Facebook’s age requirements was first reported by The Wall Street Journal. The Federal Trade Commission, which settled a suit against Facebook for consumer privacy violations last year, declined to comment on the report.

Analysts said Facebook appeared to be testing the waters for the controversial proposal after enduring a poorly executed initial public offering. Facebook’s stock dropped about 3 percent Monday to close at $26.90. That’s nearly 30 percent lower than its initial public offering price of $38.

The company would likely give limited access to underage users, analysts say. Facebook, for instance, could attach children’s profiles to their parents’ pages so the young users could play games like Farmville and connect with a controlled network of other users.

Armed with that personal data, Facebook could then sell tailored advertisements to the children, analysts said. According to child online privacy protection laws, that information can only be collected with parental consent.