As many as 7.5 million Facebook users in the U.S. are under age 13 -- a violation of Facebook's user policies -- according to a new study by Consumer Reports. Currently, Facebook requires users to submit their date of birth in order to set up an account. The information is not verified with any third-party source -- such as a credit-card company -- so as long as a user enters a birth year that is more than 13 years ago, his account will be created.

In its annual "State of the Net" survey, Consumer Reports found that privacy does not seem to be a huge concern for parents. Fewer than one in five parents with children 10 years of age and younger had "friended" their child to monitor their online posts. Interestingly, 62% of parents with 13- and 14-year-olds had.

The parents themselves are also engaging in behaviors security experts find risky, including posting birth dates, vacation plans or using Facebook Places to broadcast their locations. Only 80% of respondents indicated they had used the available privacy settings to control access to their accounts.