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Wear Looser Underwear and You’ll Get More Fertile Sperm

By Elaine Zhang, Graphics Editor

Graphic by Elaine Zhang, Graphics Editor

Many men growing up have probably heard something along the lines of this saying: Boxers over briefs means better fertility. This saying could be dismissed as pseudoscience, but new research suggests that this piece of wisdom may not be completely unfounded.

Some of the top causes of male infertility include sperm count, sperm motility (ability to move), sperm concentration, and abnormal morphology (shape and size of the sperm). A Harvard study at Massachusetts General Hospital involving 656 men between the ages of 32 to 39 surveyed participants on the type of underwear they wore, then analyzed the fertility of the semen. The results showed that there indeed is a relationship between looser underwear and higher average sperm quality, count, and mobility. Despite the men's differing height, weight, and age, men who wore boxers had an average 25% higher sperm concentration and 17% higher sperm count compared to their brief-wearing counterparts.

The most likely reason for this correlation may be the temperature-sensitive process of sperm production. Sperm production is at its highest in temperatures slightly cooler than the human body, and for that reason, the testes lie outside of the body. Long term exposure to high temperatures can reduce sperm count and cause abnormal sperm morphology. However, wearing tight briefs brings the testes closer to the body, heating up the testes and hindering sperm production and the function of the testes.

In the study, men wearing tight underwear were also found to have a 14% higher concentration of a sex hormone, FSH (follicle stimulating hormone). FSH is responsible for stimulating the testicles to produce sperm, and higher FSH in men may indicate abnormal sperm production. Raised scrotal temperatures in men wearing briefs and subsequent impaired sperm production may cause men's bodies to increase FSH to compensate for reduced sperm quality and quantity. This data provides further evidence that wearing briefs may be disadvantageous to male sperm.

Overall, the difference in sperm quality and quantity between the two groups may not significantly impact male fertility. Sperm counts found in both the tight briefs and loose boxers group were within a normal, healthy range: even in men wearing briefs, sperm counts were not reduced to the extent that fertility was diminished. It is also important to recognize that a difference in underwear and pant material may have skewed the results. Results may also not be completely representative of the general population as the population studied consisted of only men attending a fertility clinic. Thus, the true effect of underwear fit on men's fertility is unclear and perhaps inconclusive. Men who may be struggling with fertility, however, may want to consider wearing loose underwear to boost their sperm. For others, it is best to wear whatever is most comfortable: your chance of reproducing likely won't suffer too much.


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