Boxers or Briefs? The Verdict Is In  

Find out the best type of underwear for sperm count.

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You may have an opinion about whether boxers or briefs are more attractive on men – but if you’re trying to conceive, there’s potentially a better choice, a new study reveals.

Difficulty conceiving impacts roughly 8 to 12 percent of couples globally, with nearly half of those cases involving male fertility issues. While genetics, sexually transmitted diseases, and lifestyle habits play a role, underwear can matter, too. According to the study, published in the journal Human Reproduction: Boxers win.

Researchers observed nearly 700 male participants between the ages of 18 and 56 with no history of vasectomies who were looking for infertility treatment. Participants provided both semen and blood samples and filled out a questionnaire on the types of underwear they wear. Those who reported wearing boxers had a 25 percent higher sperm concentration, a 17 percent higher total sperm count, and 33 percent more active sperm. Boxer wearers also showed 14 percent lower follicle-stimulating hormone (FSH) levels compared to brief wearers (with FSH, both too much and too little can cause problems). The researchers hypothesize that FSH concentrations go up more than is optimal in brief-wearing men because the hormone is activated to compensate for testicular damage caused by the tighter underwear.

While this study did not confirm that tighter briefs and FSH levels are inextricably linked, there is an intriguing correlation, and offers a simple step for men to take. "This is something that's a relatively easy change to do," Dr. Jorge Chavarro, associate professor of nutrition and epidemiology at Harvard T.H. Chan School of Public Health, and an author on the study, told NPR. "It involves them going to buy new underwear, but that's a relatively low-cost intervention."