"Swim in the sea of life, little swimmer!"

Scientists argue about a lot of things that most of us don’t care about. But the researchers who observed about ten years back that sperm counts were falling—nationally, about one and a half percent per year—found themselves in the news. Naturally, the average guy on the street worries about his sperm being headed for extinction. Since then, there has been a lot of scientific squabbling, and Minnesota sperm have figured prominently in the controversy. As it turns out, one of the nation’s oldest and most respected sperm banks is located in Roseville. The latest information issuing from such places could gestate for hours at your next dinner party.

Where you live seems to matter. Minnesota men have sperm counts sixty percent higher than men in Missouri. Minnesota also beats California hands (tails?) down. Not only are our sperm more numerous than in Arnold Schwarzenegger’s adoptive home state, but they also appear to be healthier swimmers than California’s microscopic surfers. Though the research is cloudy, Minnesota sperm counts may be going up; at worst, they are holding steady.

It seems that Minnesota is a sperm-friendly place to live. Dr. Bruce Redmon is a professor at the University of Minnesota Medical School. He teaches urologic surgery and is a Minnesota sperm specialist. “Men in Minnesota, at least those living in the Twin Cities area, appear to have good semen quality compared to other urban areas in the U.S.,” he told me the other day. Perhaps we’ve stumbled on a new angle for the local tourism board: Impaired sperm of the world, come to the Twin Cities!

Why exactly is the Twin Cities such a sperm-friendly environment? Dr. Redmon’s studies suggest that environmental factors like pollution “raise a red flag.” One theory is that the especially toxic herbicides and pesticides used to grow fruit in California may have some nasty side effects on male fertility.

Alternatively, Minnesota winters may have something to do with it. Sperm are one of the few living organisms that thrive in winter. Some of the highest sperm counts on the planet are in frigid Finland. Researchers know that sperm counts tend to fall in warmer summer temperatures—which might explain why California, the land of endless summer, has such a lethargic sperm population. One researcher at Columbia University has correlated hard winters in Minnesota with higher sperm counts—and subsequent baby booms. In other words, if this year’s winter is especially harsh, we can expect a bumper crop of new Minnesotans next year. There is no guarantee that they won’t grow up to complain about the weather, though.—Debora Geary