Can smartphones help explain the drop in birth rates?

Apple CEO Steve Jobs unveils the iPhone in 2007. A new working paper suggests the spread of smartphones helps explain the persistent decline in birth rates in the nearly two decades since. David Paul Morris/Getty Images hide caption

Sign up for the Planet Money newsletter. The world is confusing. Economics can help.

Economist Caitlin Myers has a striking explanation for why women are having fewer babies: It's the smartphones.

Myers and other researchers have been searching for what's behind the sharp drop in fertility over the last two decades. Birth rates in the U.S. have fallen by 22% since 2007.

At first, economists assumed that the Great Recession was to blame but that births would soon rebound, as they'd done after previous downturns.

But then the economy recovered — and birth rates just kept falling.

If the recession wasn't responsible for the baby bust, what was?

"Whatever it is, it must be big, and it needs to coincide with about 2007 because that's when we see all the births go down," says Myers, a professor of economics at Middlebury College in Vermont.