A drop in US births due to smartphone use? These researchers say so.

The arrival of the iPhone nearly 20 years ago may have had a direct impact on declining birth rates, a new study argues.

The working study, which was published by the National Bureau of Economic Research but has not undergone peer review, claims the dissemination of iPhones starting in 2007 helps explains a 33% to 52% decline in the U.S. birth rate among women ages 15 to 44.

The study was done by Caitlin Myers, a Middlebury College economics professor, and her stepson, Ezekiel Hooper, a 2025 Middlebury College graduate. It focuses on where iPhones were available upon their launch between 2007 and 2011, when AT&T was the exclusive carrier for the smartphone. They then analyzed the birth rates, by county, in those areas.

For women in their 20s who lived in counties with "extensive" AT&T coverage, which meant more readily available access to iPhones, birth rates decreased by 14.6% from 2007 and 2011, Myers and Hooper wrote. Birth rates for women in their 20s who lived in counties with no AT&T coverage fell by just 10%.

Similarly, birth rates for teens who lived in counties with "near universal" AT&T coverage declined by 26% from 2007 to 2011, while birth rates for teens who lived in counties without coverage fell by 13.8%, the authors wrote.

Though the two acknowledge iPhone use is not the sole reason for the birth rate decline, Hooper told USA TODAY, he said he was surprised by how drastic the study's findings were.

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 is skeptical of the studies' narrowed focuses and how they 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 told USA TODAY. "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."

Two more studies suggest similar findings

Myers and Hooper's publication comes on the heels of two other working studies, published in April and June by the Social Science Research Network, that suggest smartphones and "the digital revolution" influenced the decline in global births because the technology affects how people spend time with one another. Both of these studies were written by University of Cincinnati economics professor Hernan Moscoso Boedo and PhD candidate Nathan Hudson.

The latter of the two studies found that 43% of the U.S. fertility decline since 2007 can be attributed to digital technology becoming cheaper, more accessible and better quality, Hudson told USA TODAY.

"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," Moscoso Boedo and Hudson say in their most recently published study. "As digital technology reallocates household time ... deep relationships erode, partnerships form less often, the partnerships that do form are weaker and conditional fertility falls."

The through line? Smartphones and other digital technologies don't make people want children any less. They are just replacing the in-person time that relationships, which may lead to children, are built on, Hudson said.

A narrowed focus into teen birth rates

The three studies all analyze a decrease in teen birth rates, claiming technology is changing how young people interact. Hudson and Moscoso Boedo's working study, published in April, specifically analyzes how smartphones have influenced teen birth rates starting in 2007.

Because more teens are hanging out online, Hudson told USA TODAY, they are having less "unstructured, in-person time." Hudson and Moscoso Boedo's teen birth rate study specifically cites the American Time Use Survey, which documented a 44% decline in in-person socializing among young people ages 15 to 19 from 2003 to 2019.

In their study, Myers and Hooper saw the largest decline − 4.5% to 8% from 2007 to 2011 − among girls ages 15 to 19, the study outlines.

"The implications for why smartphones are causing this teen birth decline we're seeing, we can't necessarily explain the cause of what they're doing on these smartphones and the changes in their behavior, we just know that smartphones are the piece playing a role in it," Hooper told USA TODAY.

But Myers and Hooper do point to a few factors considered in the study, including the time people spend with friends, people's sexual behaviors, psychological distress and a widely spread increase in search interest in pornography.

But generally, teen birth rates have been on the decline in the United States for decades, Hayford pointed out.

According to the Centers for Disease Control and Prevention, teen birth rates fell 78% from 1991 to 2021.

"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 of Ohio State 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."

Is it really possible smartphones could be causing people to have less sex?

These three studies aren't the sole analysis of the influence digital technologies like smartphones have had on relationships, sex and fertility across the globe. But there appears to be a consensus that there's an underlying impact.

Taking a look further back, Hayford said, the evolution of communication technology has long had an influence on declining birth rates, citing studies in the 1960s and 1970s that suggested the rollout of radio and television, which depicted families with just two children, disseminated the idea that smaller families were more desirable. Today that could be translated into parenting content on social media platforms like TikTok, she said.

"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."

Greta Cross is a national trending reporter at USA TODAY. Story idea? Email her at [email protected].