Weather Notebook
Bryan Yeaton
 


 
Birth Seasons
Tue Oct 26, 2004

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Birth Seasons, next on The Weather Notebook.

Does the season of your birth affect your chances of having children? According to some, yes, and more than you might expect. Hi, I’m Bryan Yeaton, and this is the Weather Notebook.

Women born in the summer have fewer children, on average, than women born at other times of the year, says a recent Austrian study of more than 3,000 women. Researchers found that the number of children born was lower among women of reproductive age born between June and August than in those born in any other month.

More specifically, women born in July had 0.3 fewer children fewer children per woman than those born in December, a decrease of 13 percent from the average of 2.24 children born per woman. These statistical results come from a sample survey that has been carried out in one percent of the Austrian population since 1967.

For men, the results are slightly different--the average number of children was highest in men born in the springtime, and lowest among those born in autumn, with intermediate values for summer and winter. The reproductive properties of men and women apparently respond differently to the season of their birth.

There could be many possible causes for the association between birth month and reproductive performance, the researchers say. In climatically temperate zones, the external environment varies with the season, and factors such as nutrition, infections, and photoperiod—the number of daylight hours experienced by each person—can all affect early development, and have an impact on later life events.

The Austrian researchers, of course, plan further studies to narrow down the possible reasons for the birth discrepancy.

David Appell sent in today’s Story. Funding for The Weather Notebook comes from Subaru of America. We are a program of the Mount Washington Observatory, home of the World Record Wind, online at www.mountwashington.org. Thanks to Trish Anderton for gluing these programs together.






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