Did iPhones reduce fertility? Two views

See Is the iPhone Birth Control? Causal Evidence from AT&T’s 2007–2011 Carrier Monopoly by Caitlin K. Myers & Ezekiel Hooper.

"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 a different shock: 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 its effect from variation in AT&T’s mobile broadband coverage. Entropy-balanced Poisson and synthetic difference-in-differences event studies imply that access to the iPhone reduced births by 4.5–8.0% at ages 15–19 and 3.2–6.6% at ages 20–24, with statistically significant but smaller declines among older cohorts. Placebo analyses applied to Verizon and Sprint’s pre-2011 coverage footprint are null. Taken together, these cohort effects imply that the diffusion of the iPhone deepened the decline in births among women under 30 while suppressing the rise in births among older women. Overall, the diffusion of the iPhone explains 33–52% of the decline in the general fertility rate among women aged 15–44. National-survey evidence on time use and sexual behavior is consistent with the iPhone reducing in-person interactions, increasing pornography use, and reducing sexual frequency."

Also see A simple reason for skepticism about the iPhones/fertility link by Tyler Cowen.

"Here is the background to the debate.  Here is more from Noah.  Here is a thread from researcher Caitlin Myers.  And here is some basic information:

In 2008, 1.9% is the share of the mobile-subscribing population with an iPhone wireless subscription.  As a percent of all adults that is 1.6%.

In 2009, it is 4.3%.  3.6% of all adults.

In 2010, 6.8%.  5.5% of all adults.

Plus conception to birth takes nine months (give or take!), noting that actual family planning may make this lag far longer.  In 2008 fertility rates already were falling pretty sharply.  The whole “maybe the iPhone messes up your dating processes” factor also requires some time to operate, especially since iPhones as a network of many many users, and whatever negative effects on socializing you think that might have, was still to lie in the future.  And what you could access on the iPhone then was far more limited than today.

So when the authors talk about diffusion explaining 33–52% of the decline in the general fertility rate among American women 15–44, I still do not get how that is supposed to operate.

The explanations I am hearing seem to be parasitic on world intuitions from 2026, not the time period under consideration."