People.com Celebrity Parents Second-Born Kids More Likely to Exhibit Troublesome Behavior Than Their Siblings, Study Finds Furthermore, second-born boys are "20 to 40 percent more likely to be disciplined in school and enter the criminal justice system" than first-born boys By Jen Juneau Jen Juneau Twitter Jen Juneau is a digital news writer for PEOPLE. A '90s teen and horror film connoisseur, she started at the brand in 2016, after a decade of working as a technical writer and then moonlighting as a journalist beginning in 2013. Originally from New Orleans, Jen grew up both in NOLA and Florida and eventually attended the University of Central Florida in Orlando (still her home base!), where she earned a bachelor's in English/technical communication, with a minor in magazine journalism. People Editorial Guidelines Published on January 25, 2019 03:45 PM Share Tweet Pin Email Photo: Getty Attention all individuals with one older sibling: You might want to reevaluate your next step. According to an in-depth study by researchers from MIT, Northwestern University, the University of Florida and more, second-born children — and, more so, second-born boys — are “20 to 40 percent more likely to be disciplined in school and enter the criminal justice system compared to first-born boys,” when discussing boys alone. The research was conducted on subjects in Denmark and Florida, finding results that were “remarkably similaracross the two locations” and taking into account “measures of infant and childhood health, parental investments, school quality and sibling composition,” according to the paper. One interesting tidbit of information, the study found, is that “maternal employment and the use of daycare is higher for second-borns in years 2 to 4 compared to older siblings” — suggesting a longer amount of parent-to-child face time could contribute to a less trouble-making future. Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Parents newsletter. Chris Tobin/Getty Images National Sibling Day: What Your Birth Order Says About Your Personality “While [first-borns have] undivided attention until the arrival of the second-born, these results show that the arrival of the second-born child has the potential to extend the early-childhood parental investment in the first-born child and a concomitant bifurcation of parental attention between first- and second-born children,” the study continues. In an interview with NPR, MIT economist Joseph Doyle, one of the authors of the paper, said he found “the results to be remarkable that the second-born children, compared to their older siblings, are much more likely to end up in prison, much more likely to get suspended in school, enter juvenile delinquency.” “Across all these outcomes, we’re getting 25 to 40 percent increases in the likelihood of these outcomes just by comparing a second-born sibling compared to a first-born,” he revealed. Brothers posing for a photo. Getty RELATED VIDEO: Former Bachelorette Ashley Hebert Rosenbaum Opens Up About Her Sibling-Rivalry Fears Another explanation? The constant presence of a younger, less mature “role model” for a second-born child — in their older sibling, as opposed to just their parents. “The firstborn has role models, who are adults. And the second, later-born children have role models who are slightly irrational 2-year-olds, you know, their older siblings,” Doyle told NPR. “Both the parental investments are different, and the sibling influences probably contribute to these differences we see in labor market and what we find in delinquency. It’s just very difficult to separate those two things because they happen at the same time.”