This past summer, The Atlantic’s Sarah Yager wrote about the rising popularity of prison nurseries as a means of saving costs, enhancing morale, and reducing recidivism among the ever-growing female inmate population. Such nurseries are, however, still fairly rare, and generally reserved for the women who give birth when they’re already behind bars and have babies 18 months or younger. Once the babies grow past that age, they’re sent out into the world to join the 3 million children in the United States who currently have a parent in custody—a population that, for policymakers, “can fade into the background.”

These children do indeed fall off the public radar, as do the 2 million or so additional U.S. children who’ve previously had a parent in prison, according to a recent Child Trends report. All in all, the report’s researchers, David Murphey and P. Mae Cooper, analyzed the National Survey of Children’s Health to conclude that more than 5 million kids—or one in 14 U.S. children—have at one time or another experienced parental incarceration. And that number, they argue, “is almost certainly an underestimate,” in part because that statistic only applies to residential parents—not parents who’ve never lived with their children. Unsurprisingly, parental incarceration is most prevalent among black, poor, and rural children.

Research has long found that children who have (or have had) a parent behind bars tend to suffer from problems including poor health, behavior challenges, and grade retention, but it’s been difficult to suss out the degree to which those issues are attributable more generally to other realities common in communities with high incarceration rates. “It can be challenging to disentangle the effects of parental incarceration from … other risk factors, such as extreme poverty,” Murphey and Cooper write. “Complicating matters further, parental incarceration can also exacerbate these associated risk factors, through loss of income, for example.”

The new report strives to do that disentangling and identify any outcomes in children that are uniquely associated with parental incarceration. And while much of the report’s findings on health outcomes and social relationships are inconclusive, one of the few risk factors that does seem to have a direct association with parental incarceration has to do with the kids’ education. Children of all ages were significantly more likely to have problems in school, while those ages 6 through 11 had lower “school engagement.” Children were considered to have school problems if they had ever repeated a grade or if their school had contacted an adult in the household in the past year about issues they were having in school. Meanwhile, “school engagement” was rated on a scale from zero to three, with children receiving a single point for usually or always meeting each of three conditions: demonstrating an interest and curiosity in learning new things; caring about doing well in school; and completing all required homework.

The researchers reason that the social stigmas associated with having a parent who is, or has been, in prison might help explain these educational challenges. “Having an imprisoned parent is an example of a loss that is not socially approved or (often) supported, which may compound children’s grief and pain, leading to emotional difficulties and problem behaviors.” A 2013 paper out of the University of Minnesota’s Children, Youth & Family Consortium also suggested that the loss of financial support resulting from parental incarceration can undermine the “family’s housing stability, the child’s living arrangement, and subsequently the child’s school stability.” Children with a parent in prison tend to struggle with chronic absenteeism, too.

The researchers also found that a child who’s had a parent in prison is more likely than one who hasn’t to experience additional “adverse childhood experiences,” or ACEs—long-term, “toxic” circumstances such as witnessing domestic or community violence, suffering from extreme poverty, or living with someone who’s mentally ill. Research has shown that ACEs, especially when they’re cumulative, often cause childhood trauma, which can ultimately result in poor immunity and mental-health problems in adulthood and even early mortality. As James Perrin, the president of the American Academy of Pediatrics, told The Atlantic’s Olga Khazan last year, “If you have a whole bunch of bad experiences growing up, you set up your brain in such a way that it’s your expectation that that’s what life is about.”

Parental incarceration often acts as one such ACE because it causes a confusing, troubling loss of an attachment figure and involves ongoing contact with law enforcement, the corrections system, and child-welfare officials. But what Murphey and Cooper find is that having a parent in prison is likely to coincide with even more traumatic experiences: Children who’ve undergone parental incarceration suffer from 2.7 ACEs on average, according to their analysis of of the National Survey of Children’s Health, which lists 8 ACEs total. Children who haven’t experienced parental incarceration suffered from 0.7 ACEs on average.

Ultimately, the researchers conclude that “the harm associated with parental incarceration can compound the already difficult circumstances of vulnerable children,” a reality that’s particularly evident in their schooling. Yet, as the University of Minnesota paper shows, education policy has done little to address these kids’ particular needs. And in this age of mass incarceration, perhaps it should. In his recent cover story for The Atlantic about the topic, Ta-Nehisi Coates described mass incarceration as a vicious cycle that victimizes entire families, holding them “in a kind of orbit, on the outskirts, by the relentless gravity of the carceral state.”

“Through it all,” Coates wrote, “children suffer.”