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ON JANUARY 9TH 2007 Steve Jobs stood on a stage in San Francisco and introduced a device that would reshape how billions of people communicate and spend their time. Less than six months later, on June 29th, the first iPhone went on sale. The queues snaked around Apple stores. The crowd that gathered at the flagship Fifth Avenue shop in New York numbered in the hundreds. Few among them, if any, were thinking about demography.
Yet a new working paper from the National Bureau of Economic Research makes the case that the iPhone—and the smartphone era it inaugurated—may have played a big role in one of the most consequential trends in rich-world economics: the sustained post-2007 decline in fertility.
The general fertility rate in the United States, which had held roughly steady at 65 to 70 births per 1,000 women aged 15–44 from 1980 to 2007, has since fallen by 22%. It stood at 54 in 2024. The decline has defied easy explanation, continuing through the economic recovery of the 2010s, through the pandemic and beyond.
Caitlin Myers and Ezekiel Hooper, economists at Middlebury College, exploit a natural experiment created by AT&T, one of America’s largest telecommunications companies, and its four-year monopoly on the iPhone. From its launch in 2007 until February 2011, the device was available in America only to AT&T subscribers. That fact allows the researchers to compare birth rates in counties with near-universal AT&T mobile broadband coverage to those with little or none, using coverage data validated by the National Telecommunications and Information Administration.
The results are striking. Access to the iPhone reduced births by 6.6 to 8.0% among women aged 15–19 and 3.2 to 6.6% among those aged 20–24, with smaller but statistically significant declines at older ages. Scaled to the national level, the estimates imply that the iPhone explains between 33 and 52% of the 2007–2011 decline in the general fertility rate. Placebo tests using coverage by Verizon and Sprint—carriers that did not offer the iPhone until 2011—produce null effects, strengthening the causal claim.
The timing is suggestive. The iPhone arrived in the same year the fertility trend broke. It diffused rapidly across every demographic group. And a descriptive literature in developmental psychology, most prominently the work of Jean Twenge and Jonathan Haidt, has documented that cohorts whose adolescence overlapped with smartphone diffusion spend sharply less time on face-to-face socialising, dating and sexual activity. Causal evidence from randomised trials of Facebook deactivation and from the staggered rollout of Facebook on college campuses supports the in-person-displacement channel.
The behavioural mechanism that Myers and Hooper propose has three parts. The first is substitution: the iPhone displaces in-person interaction, reducing the peer time in which most sexual encounters occur. The second is information: the device provides more access to contraception and abortion information, raising their use conditional on sex.
The third is substitution of a different kind: on-demand pornography, now private and always available, may substitute for partnered sex. All three channels reduce the unprotected sex that produces unintended pregnancies.
National survey data are consistent with these channels. The American Time Use Survey shows minutes per day with friends present falling by 69% at ages 15–19 between 2003 and 2024. Time alone rose by 66% at ages 25–29. The National Survey of Family Growth shows the share of women who had recent sex without contraception falling by 65% at ages 15–19 over the same period. Meanwhile Google Trends data show searches for “porn” more than doubling from 2007 to 2011, and the share of General Social Survey respondents who reported watching an X-rated movie rose substantially at every age above 25.
The heterogeneity of the effects is revealing. The declines are largest among younger women, where the iPhone’s displacement of in-person socialising would be most consequential. They are broadly similar across White and Hispanic women but absent among Black women: a finding the authors cannot fully explain but suggest may reflect differential smartphone adoption patterns or race-specific pre-existing trends that their matching procedures do not fully neutralise. There is no evidence of differential effects by parity or marital status.
The policy implications are ugly for governments that have made fertility a priority. South Korea has spent some $270bn on pronatalist programmes since 2006. France has launched a national “demographic rearmament” campaign. Japan moved to double child-related spending after prime minister Kishida warned in January 2023 that addressing the falling birth rate was “now or never”.
Yet the standard toolkit—fromcash transfers and tax credits to subsidised childcare and extended parental leave—is designed to lower the marginal cost of a child conditional on the formation of a couple positioned to consider having one.
Reviews of that toolkit reach a consistent verdict. Financial incentives do raise fertility but modestly and at steep cost. Synthesising roughly two dozen credibly identified studies, Lyman Stone finds that raising the present value of child benefits by 10% of household income increases birth rates by only 0.5 to 4.1%, with long-run effects smaller still. The short-run response merely advances the timing of births rather than raising completed family size.
The Myers-Hooper findings suggest the operative margin may be different: not the cost of raising a child but whether the relationships and sexual activity that produce children are forming at all. The iPhone effect, in their reading, operates through the formation of relationships and the time and inclination for partnered intimacy. If so, the policy instruments to which governments have committed the largest sums address the wrong problem.
The bigger question is whether the iPhone is a cause or a marker. The researchers are careful not to claim it is the sole cause of the post-2007 decline. But the timing, the geographic variation, the placebo tests and the behavioural evidence all point in the same direction. The smartphone did not create the long-run trend towards later childbearing, but it appears to have deepened and accelerated it. The cohorts whose adolescence coincided with its arrival are producing fewer children than any previous generation in North American history.
As the authors note, the fertility decline has drawn attention across the political spectrum. In May 2024 the Biden Council of Economic Advisers issued an issue brief acknowledging that historically low fertility creates “significant headwinds to economic growth” and to “the fiscal sustainability of public benefit programs”. On the 2024 campaign trail Donald Trump called for “a new baby boom”. The concern extends well beyond America.
The Myers-Hooper paper does not offer comfort to policymakers searching for levers. It suggests that the causes of the fertility decline may lie less in economic headwinds than in the private, everyday choices about how to spend one’s time and with whom. Those choices, once shaped by proximity and social obligation, are now mediated by devices that are always on and never far from hand. The iPhone is not birth control in any literal sense. But it may have changed the conditions under which children are conceived more profoundly than any policy of the past two decades. ■
