Sex And The Snowed-In Cities: Why This Blizzard Could Cause A Baby Bump

Forgive us if you've heard this (and heard it, and heard it) already: The East Coast is getting its fair share of snow this weekend.

If you have, chances are you've also heard another little anecdote. When folks get snowed in for a couple of days — the urban legend goes — the population in that area is likely to see a boost in births just nine months later. In other words: Blizzards might be prime baby-making time.

Well, it turns out there's some truth to that — and the phenomenon may not be limited just to snow storms.

"With low-level, low-severity storm advisories, we actually found an uptick in births nine months later. So, it was about a 2 percent increase with tropical storm watches," Richard Evans, a professor of economics at Brigham Young University, tells NPR's Michel Martin.

In 2008, together with Yingyao Hu and Zhong Zhao, Evans published what's considered the most definitive study yet on how catastrophic events affect birth rates. Prompted by anecdotal evidence around catastrophies — from the New York City blackout of 1965 to the 1995 Oklahoma City bombing — they decided to conduct broader, more substantive research into the phenomenon. They compared storm advisory data with fertility data on the East Coast and regions of the Gulf Coast, looking especially at differences in severity.

And those differences in severity impacted their results. The bump in births didn't hold true across the board.

"The other thing we found — that is also intuitive, but no one had ever detected this before — was that, with the most severe storm warnings ... you get almost an equal decrease in births nine months later," Evans says. "And the story there is if you're running for your life, you can't make babies."

Still, Evans says this snow storm in particular may be of the baby-making variety.

"I think the blizzard that's hitting the East Coast right now is more like a low-severity storm advisory — in the sense that, for the most part, people are not being asked to evacuate, they're not running," he says. "They're just told to hunker down in their houses for the duration of the storm until everything can get plowed and back to normal."

And as the danger diminishes, what else remains?

"If the lights go out and there's no TV, it kind of sets the table for romance, and you get births nine months later."

There's also been another funny effect of all this. Since he published the report, Evans has found himself typecast as that one guy who published a report on storms and fertility. And that's made him awfully popular among the major media organizations — especially for a scholar who usually focuses on macroeconomics and tax policy.

"I have other things that people really want to talk to me about, but this is one that keeps coming back and I can't get away from. It's a result of some really good datawork — testing an effect that was interesting — but then, it's just this topic that's irresistible by the press," he says.

"You get hurricanes and sex, and I am the guy for that — either fortunately or unfortunately."

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