A new NBER working paper uses a clever natural experiment to link early smartphone access to measurable drops in U.S. birth rates. But the picture is more complicated than the headlines suggest.
The U.S. fertility rate began falling in 2007 and has not meaningfully recovered since. For years, economists assumed the 2008 financial crisis was the primary driver — people have fewer children during economic downturns. But the economy rebounded. The birth rate did not.
A new working paper from the National Bureau of Economic Research now proposes a different explanation: the iPhone.
Caitlin Myers, an economist at Middlebury College, and her colleague Ezekiel Hooper identified what researchers call a natural experiment buried in early smartphone history. When Apple launched the iPhone in June 2007, it was exclusively available on AT&T’s network — an arrangement that held until February 2011. This created a clean geographic divide: counties with AT&T mobile broadband coverage got early access to smartphones; counties without it did not.
By comparing birth rates across this divide and controlling for confounding variables, the researchers concluded that in the first four years of the iPhone’s release, areas with access to the device saw birth rate reductions of 4.5% to 8% among women aged 15 to 19, and 3.2% to 6.6% among those aged 20 to 24.
The Mechanism: Less Time Together
The researchers do not argue that smartphones are a literal contraceptive. Rather, smartphones changed the way people — especially young adults — spend their time. They are increasingly likely to be alone, or to have interactions with friends happen online rather than in-person.
“People just aren’t forming the relationships that result in children,” Myers said.
The smartphone may have become a “substitute” for physical contact and in-person human interaction, CNN the researchers noted — a shift with downstream consequences for dating, sexual activity, and ultimately, pregnancy rates.
A separate study by Nathan Hudson and Hernan Moscoso Boedo of the University of Cincinnati supports this general direction. Analysing data from 128 countries with different healthcare systems, social policies, religions, and economic conditions, they detected the same inflection in birth rate curves — shifted in time depending on when smartphones became widely available locally. Euronews
What the Data Actually Shows — And What It Doesn’t
The effect in the Myers and Hooper paper is real, but it is concentrated in specific demographics in ways that warrant careful reading.
Among 25- to 29-year-olds, the reduction was between 1% and 1.3%; among 30- to 34-year-olds, as little as 2.7%; and among 35- to 39-year-olds, just 1.4%. Women in these age groups account for the large majority of total births.
Critically, there was “no effect” found for Black women of any age a gap the authors do not fully explain, and one that several independent researchers have pointed to as a reason for caution about broad causal claims.
The fertility drop, the authors write, is concentrated among young populations and largely operates through declines in unintended births not necessarily among women who wanted children and chose not to have them. One of the proposed mechanisms for this specific effect is simply greater access to information about contraception through smartphones.
“It’s an example of the kinds of social influences that have led to the decline in birth rate,” said Phillip B. Levine, an economist at Wellesley College who studies fertility framing the iPhone not as a singular villain, but as one visible marker in a much longer social transition.
Why It Still Matters
The declining fertility rate is an economic concern: fewer young people means fewer workers to support a rapidly growing population of seniors. Governments across the world have responded with cash incentives and family support programmes — but Myers and Hooper argue these may be targeting the wrong variables entirely. If the root cause is social isolation rather than economic pressure, financial transfers are unlikely to move the needle.
Among women, the so-called “fertility gap” — the difference between the desired and actual number of children — has recently doubled to 0.41. Many people, in other words, want more children than they are having. If smartphones are reducing the in-person social interactions that lead to relationships, that gap may not respond to economic policy at all.
The study does not offer a solution. But it does suggest that researchers and policymakers looking at birth rate decline may need to take seriously what happens when an entire generation’s social life moves to a screen.
Reference: Myers, C. & Hooper, E. (2026). Working Paper, National Bureau of Economic Research (NBER).
