Boxers or briefs? Researchers from the Harvard T.H. Chan School of Public Health have new findings that may help settle the debate.

Men who wear boxers tend to have higher sperm counts and better quality sperm than men who wear tighter underwear, according to a study published Wednesday in the journal Human Reproduction. That finding may warrant a wardrobe change among men actively looking to father a child, says study co-author Jorge Chavarro, an associate professor of nutrition, epidemiology and medicine at Harvard.

“It will definitely not harm anyone, and it will probably help the men who are likely to benefit from a small boost in their sperm counts,” Chavarro says. Based on the typical cycle of sperm production, he estimates it would take about three months of wearing boxers, after a period of wearing tighter options, to see sperm levels increase.