Shannon Stapleton / Reuters

DACA, or Deferred Action for Childhood Arrivals, is the Obama-era policy that allows 1.3 million undocumented immigrants who came to the United States as children to stay and work here legally. Those who meet the criteria are protected from deportation for a period of two years, which can be renewed.

The Trump administration plunged this program into a state of uncertainty last September. First, it announced the end of DACA, saying the program wouldn’t be accepting new applicants and that everyone would be kicked out of the program starting March 5 of this year. However, a series of temporary court rulings earlier this year blocked the program’s termination, allowing DACA recipients to continue to apply for renewals to their status, just as they had under Obama.

President Trump then said he wanted to reach a more permanent deal with Congress to protect the Dreamers, as DACA recipients are called, from deportation in exchange for funding for the border wall. But then, a few days ago Trump took to Twitter vowing to fight DACA supporters:

He seemed to reveal a lack of knowledge of the program, writing:

Immigration hawks argue that any kind of amnesty encourages more immigrants to try crossing illegally. But no one arriving in the country after 2007 is eligible for DACA, so there’s no risk of the current “flows” getting “in on” on anything.

However, Trump might want to rethink his quest to end DACA for another reason: The program seems to greatly improve the lives of its beneficiaries, in ways that, ultimately, are good for America as a whole. According to a new paper, DACA led to a big drop in teenage birth rates among undocumented youth.

Three economists, Elira Kuka, Na’ama Shenhav, and Kevin Shih, looked at education and pregnancy rates among undocumented teens between the ages of 15 and 18 who became eligible for DACA after it was implemented in 2012. Teen births declined across the whole country during that period, but to control for that, the economists compared DACA teens’ outcomes with those of immigrant teens who were already citizens—and thus unaffected by the new act. After DACA was implemented, they found, the undocumented teens were 45 percent less likely to give birth than they were before.

Like every study finding, this one has its limitations. Phillip Levine, an economist at Wellesley College who has also studied teen pregnancy, said that for various reasons, the 45 percent figure in this study might not be very precise. “I would feel comfortable concluding that DACA reduced teen fertility,” he said via email, “but I wouldn’t place too much weight on the exact magnitude of the effect.”

However, the study also found a plausible mechanism for the drop in teen pregnancies: hope for the future. DACA, the study authors found, appeared to have all sorts of other positive effects on these youths. They became more likely to graduate high school and go to college. (DACA applicants are required to either enroll in high school or get a high-school diploma.) And it didn’t seem like the teens were having less sex—but they were more likely to have protected sex.

Because DACA would ensure these teens wouldn’t be deported, it seemed they started to think differently about their futures. Graduating high school would lead to higher wages. Being lawfully present in the United States would mean they could be eligible for better jobs—and even simple things like driver’s licenses. If they made it to college, they stood the chance to make higher salaries. (Past research has shown that DACA raised the earnings of undocumented immigrants, too.) DACA seemed to change the way these teens thought about life in America. “You know that having a family is not your only option,” explained Kuka, who is with Southern Methodist University in Dallas.

Their findings echo work from other researchers, including Levine, which suggests that teens don’t necessarily get pregnant just because they’re reckless. Instead, they do so when they feel like they have few options other than parenthood. In one 2012 study, Levine and the University of Maryland’s Melissa Kearney concluded that some teens have babies when their prospects seem so limited that delaying childbirth won’t improve them by much.

This might help explain why teens in the United States, which has one of the developed world’s highest rates of income inequality, are also so much more likely to give birth than those in any other industrialized country. (A girl in Mississippi, for example, is 15 times more likely to give birth than a girl in Switzerland.) In a separate study, Levine and Kearney found that poor girls are more likely to give birth outside marriage in states with greater gaps between the poor and middle class.

“The bottom line is that when people have more of a reason to think that they can be successful, they are more likely to do the types of things that can help,” Levine said. DACA—and its associated shot at upward mobility—might help teens envision that success and delay motherhood.

Kuka and her coauthors said that if DACA is ultimately canceled, pregnancy and education trends among undocumented youth might return to pre-DACA levels. Of course, the current climate has made their futures look more uncertain, and that, they said, might be enough to deter some teens from applying for it.

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