Hedge fund Jana Partners and California State Teacher’s Retirement System (CalSTRS) aren’t Apple’s largest shareholders, but they are significant nonetheless. And it’s these two entities that just penned an open letter to Apple, urging the iPhone maker to take the lead on studying the impact smartphones have on kids and offer parents improved software tools that would allow them to better manage their children’s access to smartphone apps.

Apple introduced years ago features in iOS that allow parents to tailor iPhone and iPad use to a child’s needs. However, the two organizations want even more iOS features that would give them more granular control, consistent with a kid’s development.

As TechCrunch explains, Jana and CalSTRS have about $2 billion in Apple stock, which seems like a drop in the bucket compared to Apple’s total market cap, which is $2 billion short to reaching $900 billion right now.

But Jana Partners managing director is Barry Rosenstein, the same guy who pushed Whole Foods to put itself up for sales. Meanwhile, CalSTRS manages the retirement benefits for public educators in California, and it’s the second-largest public pension fund in the US. So their voices do matter.

Rosenstein and CalSTRS’s director of corporate governance Anne Sheehan said in the open letter that they worked with experts to review studies that found links between the use of electronic devices and adverse effects on health, sleep, empathy, and concentration.

The two organizations urge Apple to take more responsibility and reinvent parental controls in iPhone and iPad. In their opinion, the current settings offer an “all or nothing” approach, which lets parents block or allow access to certain features. They think Apple could take the lead in redefining parental controls in smart devices, to keep up with recent studies and try to prevent various health issues that may be caused by smartphone addition:

As one of the most innovative companies in the history of technology, 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. Doing so poses no threat to Apple, given that this is a software (not hardware) issue and that, unlike many other technology companies, Apple’s business model is not predicated on excessive use of your products. In fact, we believe addressing this issue now by offering parents more tools and choices could enhance Apple’s business and increase demand for its products.

Should Apple reinvent parental controls in iOS, it’s not likely to see them debut at least until iOS 12 rolls out. Jana and CalSTRS are right about one thing. More advanced parental controls would qualify as a major selling point for Apple devices.

The full open letter to Apple is available at this link.