Smartphones and the Fertility Cliff: New NBER Study Quantifies iPhone's Role in U.S. Birth Rate Decline

A June 2026 National Bureau of Economic Research working paper by economist Caitlin K. Myers of Middlebury College and her student Ezekiel Hooper provides causal evidence that the diffusion of the iPhone explains 33–52% of the 22% drop in the U.S. general fertility rate among women aged 15–44 since 2007.

The study exploits Apple’s exclusive 2007–2011 partnership with AT&T as a natural experiment. Counties with greater early AT&T mobile broadband coverage saw sharper fertility declines, particularly among women under 30. Access to the iPhone reduced births by an estimated 4.5–8.0% at ages 15–19 and 3.2–6.6% at ages 20–24, with smaller but significant effects in older cohorts. Placebo tests on pre-2011 Verizon and Sprint coverage areas yielded null results, strengthening the identification strategy.

National survey data on time use and sexual behavior align with the mechanism: smartphones appear to have reduced in-person social interactions, increased pornography consumption, and lowered sexual frequency. The authors are careful not to claim the iPhone is the sole driver—factors such as the Great Recession, housing costs, and changing norms remain relevant—but argue that conventional explanations fall short of accounting for the sustained post-2007 decline.

The finding resonates with a parallel May 2026 paper referenced in The New York Times that also links smartphone adoption to fertility trends. Together, the studies move the conversation beyond correlation toward quantified technological impact on demographic patterns long observed in developed nations. Broader implications include potential effects on social skill development among younger cohorts and the acceleration of population aging already underway in the United States.