PUT. THE SMARTPHONE. DOWN. Why Are Birthrates Down? You Might Be Looking at the Answer.

Caitlin Myers, an economist at Middlebury College, and Ezekiel Hooper, her student, used the spotty early rollout of the iPhone as a way to isolate the effects of the phone on fertility. The first iPhone was released in June 2007, they wrote, and was available only on the AT&T network until February 2011. The study compared fertility rates in U.S. counties that had near-universal AT&T coverage with counties that had little or none.

Their paper, published in the National Bureau of Economic Research, found that the iPhone caused as much as half of the fertility decline between 2007 and 2011. The most pronounced effects were among young people aged 15 to 24.

What happened in the counties with iPhones? One theory, Professor Myers said, is that young people began to socialize more on their phones and less in person, and consequently were less likely to have sex and become pregnant.

Professor Myers said iPhones may also have made pornography more accessible, which led young people to substitute it for sex, or young people may have used them to obtain better information on avoiding pregnancy, including contraception and abortion.

Researchers not involved in the study said the results were persuasive.

Makes at least as much sense as any other explanation I’ve seen.