The introduction of the iPhone may have contributed substantially to America's falling birth rate, suggesting smartphones changed social behaviour in ways that led to fewer pregnancies, researchers have argued.
A new working paper published by the National Bureau of Economic Research (NBER) says that early smartphone adoption could explain between 33% and 52% of the decline in the US general fertility rate between 2007 and 2011.
The paper, authored by economist Caitlin K Myers of Middlebury College and her stepson, researcher Ezekiel Hooper, is the latest contribution to a long-running debate over why US birth rates have continued to decline even after the recovery from recession.
It notes that the general fertility rate has dropped by around 22% since 2007 despite no single economic explanation emerging.
In their paper, ‘Is the iPhone Birth Control?’, Myers and Hooper argue that any convincing explanation must be “big,” “dated,” and “broadly distributed” across demographic groups.
Building on earlier research that identified the iPhone, email and social media as possible drivers of a “cohort-level shift in priorities,” they sought to test whether the arrival of smartphones could have had a measurable impact on birth rates.
To do so, they took advantage of what economists describe as “a natural experiment.”
When Apple launched the first iPhone on June 29, 2007, it could only be used on AT&T's mobile network under an exclusive agreement that lasted until February 2011.
Counties with extensive AT&T 3G coverage therefore gained access to the iPhone years before counties where its coverage was limited.
Comparing counties with more than 90% AT&T coverage against those with less than 10%, the researchers found consistently larger declines in births where early smartphone access was greatest.
Their estimates suggest early iPhone access was linked to births among women aged 15 to 19 being 4.5% to 8% lower than they might otherwise have been. Births among women aged 20 to 24 were similarly affected, being an estimated 3.2% to 6.6% lower.
Smaller but statistically significant reductions were also observed among older age groups.
Overall, the authors estimate that smartphone adoption explains between a third and half of the decline in the US general fertility rate during the study period.
The effects appeared broadly similar among white and Hispanic women, although the researchers said they could “estimate no effect” for black women - a finding they acknowledge is “harder to reconcile with the broad smartphone-diffusion story”.
The study also found no meaningful differences according to marital status or whether women had previously given birth, although there was some variation by education level - ranging from a 2.1% decline among college graduates to a 5.8% decline among women with some college education but no degree.
To test whether their findings were simply reflecting differences between mobile networks rather than smartphones themselves, the researchers carried out placebo tests using Verizon and Sprint coverage during the period when those carriers did not yet offer the iPhone.
They found no comparable effect before 2011 but did observe similar declines once Android smartphones became available on those networks.
The authors argue that this corroborates the “broader smartphone reading” rather than undermining their conclusions.
The paper does not argue that smartphones in themselves reduce biological fertility. Instead, it proposes three possible behavioural mechanisms that could have contributed to fewer pregnancies: reduced face-to-face socialising, greater access to contraception and reproductive information, and increased consumption of online pornography.
Myers and Hooper stress that these mechanisms are not causally tested but are supported by descriptive evidence showing Americans spent less time with friends, reported declining rates of recent sexual activity alongside increased contraceptive use, and exhibited rising online interest in pornography during the study period.
The researchers suggest that if smartphones have fundamentally altered relationship formation and social interaction, governments seeking to reverse falling birth rates may need to rethink current policy approaches to take these into consideration.
They note that conventional pronatalist policies such as cash payments and subsidised childcare “do raise fertility, but modestly and at steep cost”.
If declining fertility is increasingly driven by changes in relationships rather than the financial burden of raising children, they argue, existing policy tools may be addressing the wrong problem.
“The operative margin may be less about the cost of raising a child and more about whether the relationships and sexual activity that produce children are forming at all,” the researchers wrote.
The authors acknowledge that attempts to estimate the effect among individual iPhone owners are “fraught”, since smartphones likely influence behaviour at a broader social and network level rather than only through personal ownership.
Nonetheless they conclude: “We do not claim that the iPhone is the sole cause of the post-2007 decline, nor that no policy lever can move the trajectory. But over the 2008–2011 window that our design identifies, our estimates imply that the introduction of the modern smartphone played a sizable role in the decline in US births.”
The study has already attracted discussion among other researchers.
Speaking to CNN, Dr Alison Gemmill, an epidemiologist at UCLA whose work examines US fertility patterns, agreed smartphones may have influenced relationship patterns but cautioned that they have done so alongside “major changes in housing costs, education, labour markets, gender norms, and social life,” adding that “untangling those factors is challenging.”
Also speaking to CNN, Ohio State University sociologist, Dr Sarah Hayford, questioned whether a technology introduced in 2007 could explain a decline that stretches back many decades. She also pointed to expanding access to longer-lasting contraception during the same period as another important factor.
