Is the iPhone Birth Control? Causal Evidence from AT&T's 2007–2011 Carrier Monopoly
NBER Working Paper 35310, 2026
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. The iPhone's 2007–2011 exclusivity on AT&T offers a natural experiment, identifying 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, with no evidence of a negative effect at ages 25–29 and declines again 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.