Is the iPhone Birth Control? Causal Evidence from AT&T’s 2007–2011 Carrier Monopoly

The U.S. general fertility rate has fallen by 22% since 2007, a sustained decline not readily explained by economic conditions, contraceptive use, housing or childcare costs, or other commonly cited factors. We assess the potential role of the diffusion of the smartphone. The U.S. rollout of the iPhone, the first modern smartphone, provides a natural experiment: from June 2007 through February 2011, the device was sold only on AT&T, allowing us to identify the effect of smartphone access from variation in AT&T’s mobile broadband coverage. Poisson and synthetic difference-in-differences event studies imply that access to the iPhone reduced births by 2.0–9.0% at ages 15–19 and 1.5–7.2% at ages 20–24. We do not observe evidence of a negative effect at ages 25–29, and again observe declines at ages 30–44. Overall, the early diffusion of the smartphone explains 12–53% of the 2007–2011 decline in the general fertility rate. National trends in time use and sexual behavior are consistent with the iPhone reducing in-person interactions, increasing pornography use, and reducing sexual frequency.