For many of us, the name Bill Gates or Steve Jobs is synonymous with tech innovations. But even though they helped make personal computers and smartphones widely available to the general population, they were both much stricter when it came to granting internet access to their own kids.

Gates’ technology rules are simple: His three kids—now 15, 18 and 21 years old, respectively—couldn’t own a cell phone until age 14. They weren’t allowed to use their phones at the dinner table. And don’t even think about bringing that phone to bed after lights out.

You may think an industry leader would be a little more lenient on tech use. But once you learn his reasoning, you’ll understand why the Microsoft co-founder is strict. Speaking to The Mirror in 2017, Gates said, “You’re always looking at how it can be used in a great way—homework and staying in touch with friends—and also where it has gotten to excess.”

The late Steve Jobs also set limits on his kids’ technology use. In fact, Jobs, who was Apple’s CEO until he passed away six years ago, told The New York Times in 2011 that he banned his children from using the iPad he helped invent.

Personal screen time is increasing among youth: A report released last year by Common Sense Media found 42% of kids ages 8 and younger now have their own tablets—a 41% jump from 2011. That same study revealed that young children also spend at least an hour a day glued to their mobile screens; in 2013, it was only about 15 minutes.

And the effects of screen time are worrisome. A 2017 Clinical Psychological Science study found that teenagers who spent more time with their mobile devices than socializing in person were more likely to report mental health issues such as depression. Though the research doesn’t show causation, experts told the Daily Beast a correlation is clear.

Now two major Apple investors want tech giants to take responsibility. In an open letter to Apple, the California State Teachers’ Retirement System and JANA Partners, two groups that own a combined $2 million in Apple shares, have urged the Silicon Valley company to study the effects on smartphone use on children, as well as expand parental control options on its products.

In a letter dated Jan. 6, the shareholders wrote, “Apple can play a defining role in signaling to the industry that paying special attention to the health and development of the next generation is both good business and the right thing to do.”

This, of course, is not to say technology doesn’t have its advantages. Assistive technology, for example, is an amazing tool for children with disabilities to become immersed in learning. And, as a whole, technology can make learning more interesting and fun, which can engage more children.

None of us want our kids to become dependent on smartphones, tablets and other mobile devices. So it starts with us—the parents—through the positive examples and restrictions we set.