Smartphone use tied to 33-52% drop in US births, study suggests

iPhone rollout – A new, unpublished National Bureau of Economic Research working paper argues that the spread of iPhones from 2007 to 2011—when AT&T was the exclusive carrier—helped drive a 33% to 52% drop in U.S. birth rates for women ages 15 to 44. But researchers and demogr

For families and policymakers tracking America’s falling birth rates, the newest argument comes with a familiar, daily adversary: the iPhone.

A working paper published recently by the National Bureau of Economic Research. and not yet peer reviewed. claims the rollout of iPhones beginning in 2007 explains a 33% to 52% decline in the U.S. birth rate among women ages 15 to 44. The study looks at where iPhones were available after launch between 2007 and 2011. when AT&T was the exclusive carrier for the smartphone. and then analyzes birth rates by county in those areas.

The findings are striking in their precision. For women in their 20s living in counties with “extensive” AT&T coverage—meaning more readily available access to iPhones—birth rates fell by 14.6% between 2007 and 2011. according to the authors. Birth rates for women in their 20s in counties with no AT&T coverage fell by just 10%.

The pattern also shows up for teens. Among teens living in counties with “near universal” AT&T coverage, birth rates declined by 26% between 2007 and 2011, while birth rates for teens in counties without coverage fell by 13.8%, Myers and Hooper wrote.

The researchers behind the work are Caitlin Myers. an economics professor at Middlebury College. and her stepson. Ezekiel Hooper. a Middlebury College graduate from 2025. Their analysis also points to where the decline was strongest for teenagers: they saw the largest drop—4.5% to 8%—between 2007 and 2011 among teen girls ages 15 to 19.

Hooper said he was surprised by how drastic the study’s results were, while also saying he understands iPhone usage is not the sole reason birth rates declined between 2007 and 2011.

That caveat sits uncomfortably beside the paper’s headline implication: that the smartphone itself may have been a major driver of fertility changes over a five-year window.

Sarah Hayford. director of the Institute for Population Research at Ohio State University. said she is open to considering smartphones’ effect on birth rates in the United States and abroad. But she also expressed skepticism about the studies’ narrowed focus and how they might affect the wider discussion around falling birth rates globally.

“This is partly how sociologists look at the world and how economists look at the world. but as a sociologist. I’m not particularly interested in explaining this little blip of a five-year trend. ” Hayford said. “I’m sort of more interested in thinking about what are the big-picture things driving really long-term changes in family formation and childbearing.”.

The dispute isn’t only about whether phones matter—it’s about whether this particular mechanism matches what researchers know about why teen births fell.

Two other working studies, published in April and June by the Social Science Research Network, offer similar arguments that smartphones and the “digital revolution” have influenced the decline in global births by changing how people spend time with each other.

One of those studies. authored by University of Cincinnati economics professor Hernan Moscoso Boedo and PhD candidate Nathan Hudson. argues that 43% of the U.S. fertility decline since 2007 can be attributed to digital technology becoming cheaper and better quality. Hudson said this in a summary of the study’s conclusions.

In the study. Moscoso Boedo and Hudson wrote that “The digital revolution has fundamentally reshaped how humans interact with one another. favoring broad and shallow connections at the expense of the deeper ones that require sustained in-person investment.” They add that “As digital technology reallocates household time … deep relationships erode, partnerships form less often, the partnerships that do form are weaker and conditional fertility falls.”.

In Hudson’s telling, the throughline is not that digital technology makes people less interested in having children. Instead, he argued, it replaces in-person time—the kind of time relationships may be built on—so the effect shows up in how partnerships form and in fertility outcomes.

Another of the three studies. also authored by Myers and Hooper. zeroes in on teens and begins its analysis with smartphone exposure starting in 2007. Hudson said teens are spending more time online. leading to less “unstructured. in-person time.” That study cites the American Time Use Survey. which documented a 44% decline in in-person socializing among teens ages 15 to 19 between 2003 and 2019.

Hooper said the implications for why smartphones could be causing the teen birth decline cannot necessarily explain the precise cause of what teens do on their phones. Still, he said the studies “just know that smartphones are the piece playing a role in it.”

Myers and Hooper point to factors considered in their analysis: the time people spend with friends, one’s sexual behaviors, psychological distress, and a widely spread increase in search interest in pornography and X-rated movie viewing.

But Hayford pushed back against one specific part of the proposed story: the idea that smartphones may reduce sex.

“[Teen birth rates] have been on the decline in the U.S. for decades,” Hayford said. She cited Centers for Disease Control and Prevention data showing teen birth rates fell 78% from 1991 to 2021.

Hayford said she believes the best evidence on why teen births fell in the years around and after 2007 points to increased contraceptive use, not decreased sex.

“In the U.S. at least. we have pretty good evidence about declining teen birth rates. starting around 2007 in that five- to 10-year period. And the evidence we have suggests the reason birth rates fell among teens … is because of increased contraceptive use and not because of less having sex,” Hayford said. “That seems kind of not consistent with the mechanism that these studies are proposing. that socializing online kind of displaces socializing offline. including having sex.”.

The smartphones-on-relationships argument also runs into a larger question about time horizons: whether a short, tightly defined technology shift can explain changes unfolding across decades.

The three studies are not the only analyses of how digital technology affects relationships, sex, and fertility across the globe. Hayford said the broader consensus appears similar—there is an underlying impact. She also noted that changes in communication technology long predate smartphones.

Looking further back. she said studies from the 1960s and 1970s suggested that the rollout of radio and television. which depicted families with just two children. helped spread the idea that smaller families were more desirable. Today, she said, the parallel could be parenting content on social media platforms like TikTok.

“Falling fertility rates is something that’s happening all over the world in all sorts of age groups and very different contexts. ” Hayford said. “And as we’re thinking about explanations for that. we want to think about the big picture and the long term. and I’m not sure that these micro. super-focused studies are the most helpful way to think about the picture changes and trends.”.

Across the debate, one tension keeps returning: the studies can trace technology exposure with tight geographic comparisons and time windows, yet the real world of fertility decisions doesn’t turn on a single device.

In the meantime, the research adds fresh fuel to a national argument that many Americans already feel in their daily lives—how long screens keep us apart, what that changes about dating and intimacy, and whether the timing of the iPhone boom matches the timing of the birth-rate drop.

birth rate iPhone smartphones AT&T exclusive carrier 2007 2011 teen births fertility decline National Bureau of Economic Research Middlebury College Caitlin Myers Ezekiel Hooper Hernan Moscoso Boedo Nathan Hudson digital revolution American Time Use Survey