Some privacy advocates were rankled when Facebook announced changes to its policies last week that allow teens to post public updates that can be viewed by anyone in the world.

But Facebook has contemplated another rule change that could prove even more controversial.

Facebook's manager of privacy and safety says the social network has "thought a lot about" opening up the site to children under the age of 13.

Because despite the current rules stating that you have to reach your teens before signing up for Facebook, plenty of young kids are using the site anyway, often with the help of their parents.

"In the U.S., the Children's Online Privacy and Protection Act starts at 13 and it says that companies shouldn't collect information from kids ... if they're under the age of 13 without parental consent, so that's a law we abide by," said Nicky Jackson Colaco in a recent interview.

She acknowledged that Facebook has discussed ways of letting kids under 13 use Facebook without violating the act.

"It's something we've thought a lot about, we've actually been asked by a lot of different people to open up the site. It's something that obviously we would approach very, very thoughtfully with a lot of outside advice from safety experts, advocates and public figures," Colaco said.

Some 20,000 underage accounts deleted daily

"We would really just want to make sure that we entered into any decision like that very responsibly, but yes, it's something we think about. But we have not made any plans or move into that market yet."

In 2011, a Facebook official was quoted as saying that about 20,000 underage accounts were being deleted every day.

Colaco said her position is that parents shouldn't help their kids break the rules to get on Facebook early.

"I think there are parents who make the decision that it's appropriate for their kids and we really encourage parents to have their kids wait until they're 13 and follow that guideline that we have," she said.

"First and foremost it's a policy of the company, it's one of the terms of service. A lot of times what we say is, as parents — I'm a mom of two — we don't want to sanction lying and so just as we wouldn't sanction lying in other parts of our lives, it's good not to do it online."

Canada wants consultation

A spokesman for Canada's privacy commissioner Jennifer Stoddart said in a statement that consultation would be important if Facebook planned to begin accepting younger users.

"If this is something the company is actively considering then our office would hope to be consulted on any such proposal and to provide comments," said Scott Hutchinson.

"We would need to look at the mechanism the company would put in place in order to obtain parental consent, as well as the measures it would take to ensure children's information would not be shared with or accessed by an unintended audience."