Men who wear boxer shorts produce higher quality semen, study finds

It's the largest study to examine the relationship between underwear choice and sperm quality

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You can't judge a book by it’s cover, but perhaps you can judge a man by his underwear, as a new study suggests that the boxers vs briefs debate is more than just a matter of taste.

According to research published in the journal Human Reproduction, men who wear boxer shorts benefit from both a higher sperm count and concentration than men who opt for tight-fitting varieties of underwear, such as briefs and jockeys.

The study is the largest of its kind and also revealed that men who wore boxers also had lower levels of follicle-stimulating hormone (FSH), which stimulates sperm production as compensation for testicular damage that has arisen as a result of increased scrotal temperatures and decreased sperm count and concentration.

A total of 656 men aged between 18 and 56 were involved in the study, which examined a number of previously unexplored variables related to testicular function, such as sperm DNA damage and reproductive hormones.

According to the team of Harvard researchers, including this information was crucial in fostering a deeper understanding of how underwear choices affects sexual development in men.

Participants were recruited via calling on male partners in couples who were seeking fertility treatment at the Massachusetts General Hospital between 2000 and 2017.

Each person had an average BMI of 26 and was asked to provide blood and semen samples in addition to answering a questionnaire that asked for details on their underwear preferences and required them to state which style they had worn the most in the last three months.

53 per cent of participants said they had mostly worn boxer shorts and, according to the researchers, these men were typically younger and slimmer than those who wore tighter-fitting varieties of underwear.

These men boasted a 25 per cent higher sperm concentration and 17 per cent higher total sperm count than those who avoided wearing boxers.

They also possessed 33 per cent more swimming sperm in a single ejaculation.

As for differences in sperm DNA damage and reproductive hormones, the researchers concluded that there were no significant imparities.

Speaking to The Independent, lead author Dr Lidia Mínguez-Alarcón, a research scientist at Harvard T.H. Chan School of Public Health, explains that her findings were consistent with previous studies on the correlation between underwear choice and sperm production.

However, it marks the first time that any research has revealed that men who wear tighter underwear also have higher FSH levels, which she argues suggests that “a potential compensatory mechanism” might be in effect for these men.

“These results could be used to improve the sperm counts of men, since type of underwear worn is a modifiable lifestyle and spermatogenesis (sperm production) is estimated as taking around 90 days,” she adds.

“Results from this study are very practical, since men could improve their sperm production by easily changing their type of underwear worn to boxers.”