Parents should adopt a rule when it comes to technology: If the individuals who created a device or social network won’t post their children on it, neither will I.

Like most Americans, you probably use social media to keep in touch with everyone from your high-school friends to colleagues, posting updates about your family, your kids’ pictures and more. But should you?

It’s instructive to look at how Facebook’s creator, Mark Zuckerberg, and his wife, Priscilla Chan, use their very own social network. The last time Zuckerberg posted a photo of their two children on Facebook was Thanksgiving, more than eight months ago. Chan posted a shot at the end of April, an overhead photo of her daughter, Max, playing a game. Notably, she seems to have never publicly posted a photo of either of her kids’ faces.

Zuckerberg isn’t the only tech titan skittish about his family members’ presence online.

It’s impossible to find a single photo of Snapchat CEO Evan Spiegel’s child, Hart, on his wife Miranda Kerr’s Instagram account — even though the model must be tempted to share baby photos with her 12 million followers.

Tech titans like Bill Gates and Steve Jobs famously limited their kids’ access to technology. And last year, Apple CEO Tim Cook told The Guardian: “I don’t have a kid, but I have a nephew that I put some boundaries on. There are some things that I won’t allow; I don’t want them on a social network.” (Cook’s nephew was 13 at the time.)

They have good reason to be wary. Earlier this month, The New York Times broke a story about YouTube that sent parents scrambling to adjust their privacy settings. Times reporters Max Fisher and Amanda Taub revealed a disturbing aspect of the video site’s playlist algorithm, which could troll through innocent family videos to put together images of semi-nude kids for pedophiles.

“Any user who watched one kiddie video would be directed by YouTube’s algorithm to dozens more — each selected out of millions of otherwise-obscure home movies by an incredibly sophisticated piece of software that YouTube calls an artificial intelligence,” wrote Fisher on Twitter, explaining their findings.

“The families had no idea. We talked to one mother, in Brazil, whose daughter had posted a video of her and a friend playing in swimsuits. YouTube’s algorithm found the video and promoted it to users who watched other partly clothed prepubescent children. Within a few days of posting, it had 400,000 views.”

This came as no surprise to one Indiana mother and social-media marketer, Ericka, who recently noticed the trend with videos of her own child. Ericka told me how she used YouTube as a backup server for videos of her kids. The videos were never shared and received no views, so she never gave much thought to putting them online. Then, while she was uploading to her YouTube channel one day, she noticed one of her videos had an exceptionally high number of views. It featured her young son in the bathtub, and in it a bit of his behind was visible.

“It looked so innocent, and I didn’t think anything of it,” she told me. “I went back to it a few days later [and] I noticed the view count had gone up significantly. It had 5,000 views. It freaked me out, and I immediately took it down.”

Jason Howerton, a new father from Texas, also shared this frightening story with me.

“For the first year of my son’s life, I was thrilled to share my journey as a dad on Twitter — cute pictures and videos of my son dancing and such. I’ve never been more proud about anything as I am about being a father. I really never thought anything of it until someone broadcasted his face from my Twitter profile in a Periscope rant attacking me about politics. Right there, in the middle of a fiery partisan video, was my baby son’s face.

That really was a lightbulb moment for me. It is my job as a father to protect my son from any and all threats, no matter how small or unlikely. When you [share] photos of a non-consenting child on an open platform like Twitter that is accessible to millions and millions of people, some of whom may be mentally unstable, you are taking a risk.”

‘It looked so innocent, and I didn’t think anything of it’

In 2002, then-Secretary of Defense Donald Rumsfeld faced mockery when he said the most dangerous risks a country faces aren’t “known knowns” but “unknown unknowns.” Many parents knew about the risks of bad guys on the Internet, and maybe even about facial-recognition technology tracking their kids across the web. But the situation with YouTube was an unknown, a scenario so heinous it defies the imaginations of most.

Now parents know more about the full scope of dangers on the Internet and the fact that a major technology company was making it easier and more appealing to turn children into sexual objects. One of those unknown unknowns is now known, and it’s hard to believe there aren’t more out there perhaps even more horrifying than this.

There are few in the world who can grasp the dangers of growing up on the Internet, and almost all of them are the architects of the technology that built it. If the Mark Zuckerbergs of the world keep their kids offline, more American parents should be taking the hint about where our children belong, and where they don’t.