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Apple's parental restrictions block sites that blatantly mention sex, but let some pornographic or extremist ones through.

Apple/Screenshot by CNET

The restrictions are accessed within Screen Time, which Apple added in September's iOS 12 update, and let you stop kids from stumbling upon inappropriate content on iPhone web browsers.

But sex education site O.school pointed out that the feature blocks searches for "safe sex" and "how to report sex abuse," but allows you to reach some pornographic subreddits and the neo-Nazi site Daily Stormer.

We checked out the restrictions and found that they seem to center on the word "sex" and obvious sex-related topics, but aren't broad enough to catch other inappropriate ones.

Parents can take a more direct approach by using Screen Time to only allow their kids to visit certain sites or by blacklisting a customized set.

Apple didn't immediately respond to a request for comment.

It's not the first time Screen Time's limits have been tested. Parents complained that their kids discovered several workarounds for the Screen Time limits within days of iOS 12 going live.