Requiring a slightly cooler than core body temperature, the vital processes of sperm creation and storage drove Mother Nature to an inelegant solution: Hanging the primate testes between the legs, just outside the body.

But with his sartorial wisdom, man devised a most elegant cover-up, at least according to the Scottish. First worn in the Highlands, the "walking kilt" freed working men from the "cumbrous and unwieldy" belted plaid. Soon, the knee-length garment became a popular symbol of Scottish culture and pride, associated today with bagpipers and robust men of Northern European descent.

However, the garment may also promote male fertility, researchers reported in the latest issue of the Scottish Medical Journal. Conducted last year, the study suggests that looser-fitting male garments — as opposed to briefs — are associated with significantly higher sperm counts.

"Based on literature on scrotal temperature, spermatogenesis [or the process of sperm development] and fertility ... men who regularly wear a kilt during the years in which they wish to procreate will, as a group, have significantly better rates of sperm quality and higher fertility," the study authors wrote.

Sperm quality in men might also be hurt by other activities that raise the scrotal temperature, such as using saunas and sitting with laptops, other researchers have found. Larry I. Lipshultz, M.D., chief of the division of male reproductive medicine and a professor of urology at Baylor College of Medicine, says just a third of a degree in temperature can make a difference. "Studies have shown that applied heat-like the heat from hot tubs or direct contact with heating pads-really can impair [sperm production]," he said. "But research looking at the effects of tight underwear and indirect heat has been very iffy."

Nevertheless, the study authors recommended "regimental style" — also known as "going commando" or not wearing any underwear — as the most beneficial way to wear a kilt.

The researchers further noted a strong psychological benefit to wearing such a fine and masculine garment, an effect which might boost testosterone, and therefore fertility. "There are strong psychological benefits associated with kilt wearing," the researchers noted, "most notably a feeling of masculinity and pride, and positive attention from sexual admirers."

"Because the kilt is a purely masculine garment, men need not be ashamed of or reticent about the therapeutic wearing of a kilt for a certain period of time to possibly improve sperm quantity and quality."

The researchers qualified their conclusions by noting that "further researcher is needed to prove this hypothesis."