A news flash that won’t surprise anyone: Screen time is bad for young kids. The latest such reminder came from a systematic review conducted by a consortium of British researchers, who found that more screen exposure for toddlers is consistently associated with less interaction between the parent and child, as well as delayed development, sleep issues, and eating problems. The authors determined that children under 2 should not get any intentional screen time.

The review was performed under the auspices of a nonprofit called the 1001 Critical Days Foundation; the organization’s founder, Andrea Leadsom, told The Guardian that the conclusions were a “wake-up call.” But I am guessing that most readers of The Guardian are already awake. Richer, highly educated parents—the kind who have the time and resources to read the news and incorporate the warnings of experts into their child-rearing—are already more likely to limit their kids’ screen time than less educated, lower-income parents are.

High-earning and highly educated parents are likelier to follow all sorts of parenting advice on things such as breastfeeding and baby-led weaning. Because of this, researchers may never truly know if the advice appears to work because it’s good advice or because of the particular characteristics of the families who follow it. The unspoken secret of the parenting-strategies world is that, much of the time, the best parenting hack is just being rich.

[Read: Doomed to be a tradwife]

Of course, wealthy parents can be irresponsible, and low-income parents can create loving, enriching homes. A high household income doesn’t guarantee a good childhood. But researchers have observed for decades that the children in families with more resources tend to have better outcomes in many areas of life. Greg Duncan, a professor at UC Irvine who has studied child poverty for many years, told me that this is because rich parents are better able to provide a home environment that leads to success. They are also able to afford to live in safer neighborhoods and send their kids to better schools, and to some extent they pass genetic traits such as high conscientiousness and IQ on to their kids. (In this story, I use parental income and education somewhat interchangeably, though education—especially the mother’s education, according to Duncan—seems to have a stronger effect on a child’s life outcomes than parental income.)

Consider how this all plays out with screens: High-income parents expose their kids to much less screen time than low-income parents do. A recent report from Common Sense Media found that children living in households earning less than $50,000 a year spend twice as much time with screens as children from households earning $100,000 or more. A Pew report found that low-income parents were more permissive with all sorts of screen time: They were more likely than high-income parents to let their child watch YouTube daily, for example, or to use smartphones to calm their child down.

These differences likely stem from the fact that keeping kids off screens requires time and money—which wealthy parents tend to have more of. Rich parents can hire sitters and nannies to watch their kids while they work or do chores. They can afford Instacart, DoorDash, and other labor-saving services. They are more likely to enjoy flexible and remote work, which can give them more time to engage their kids in screen-free activities. They may have desk jobs that allow them to browse the internet between meetings and read articles filled with parenting tips. Finally, many rich parents have more vim and vigor left over at the end of the day to enforce boundaries. “One of the things income buys you is there are less other stressors in your life,” Emily Oster, an economist who founded the ParentData newsletter and has written books on pregnancy and parenting, told me. “You have more emotional and physical and psychological energy to spend” on keeping your kid off the tablet.

In many studies, researchers attempt to control for confounding variables such as income and education. But these efforts come up against an issue called “residual confounding”: differences between families that a study may not pick up on. Research exploring the effect of screen time on, say, test scores, might find that an iPad-free family has kids who aced the ACT. But the high scores could be the result of some other parenting strategy that the no-screen-time parents used. Oster told me that when she was a girl and her brother was preparing to take the SAT, her parents placed vocabulary words under their dinner plates, and the children were supposed to use them in conversation during dinner. This is a unique behavior that researchers would not ask about in a screen-time study, even if they controlled for income and education.

[Read: American kids used to eat everything]

Together, the issues of confounding variables and residual confounding plague much of parenting research. Breastfeeding is linked to higher IQs in children, but mothers with higher IQs are more likely to breastfeed, and because IQ is partly genetic, their kids would probably have higher IQs anyway. Plus, privileged mothers are also more likely to have the kinds of professional jobs that provide paid parental leave so that they can breastfeed. The consumption of ultra-processed food has been linked to childhood obesity, but thinness is partly genetic, and rich parents tend to be both thinner and more likely than low-income parents to feed their kids healthy food, in part because they can afford to buy more fruits and vegetables. Across the board, wealthier, more educated parents have all sorts of advantages that less-privileged parents can’t easily replicate, no matter how forcefully they’re urged to do so.

Because I am a highly educated mom with many resources, I shell out for music classes that I dutifully cart my toddler to on Sundays, only for him to ignore the instructor, run around the room, and attempt to stick his finger into every electrical socket. But hey, at least he’s not using a screen. Meanwhile, a woman in a moms’ Facebook group that I’m part of recently posted about how her 18-month-old gets about three hours of screen time a day. She is solo parenting while her husband is away on a military assignment, she wrote, and she is trying to start a business and get chores done while her son plays. Reading her message, I wasn’t sure what her options were other than screens.

Rather than scolding parents about screens, society could do more to support families in ways that obviate the need for screen time. Community centers could offer more affordable activities for kids. The government could subsidize child care for more families. Companies could provide more remote-work options so that parents don’t have to cook dinner at 6 p.m., just as their toddlers’ moods hit a nadir and screen time is at its most appealing.

But until any of this happens, I am left agreeing with the sentiment of one commenter on that woman’s post about solo parenting: “Do what you need to do.”