Boxers or Briefs: Harvard Study Examines Effects on Fertility

It’s no longer merely an urban legend nor a harmlessly snarky question asked by overly curious folks. The boxers versus briefs debate recently gained a new wrinkle: A Harvard study indicates that underwear choices might involve more than aesthetic preferences.

A man’s choice to wear a particular style could, in fact, impact levels of sperm concentration, as well as other aspects of male fertility.

The August 2018 study, published in the journal Human Reproduction and entitled “Type of underwear worn and markers of testicular function among men attending a fertility center”, involved 656 male subjects and examined whether self-reported types of underwear worn by men were connected to markers of testicular function.

The study’s conclusion: Men who said they wore boxers more often tested as having elevated sperm concentration and overall count when compared to men who wore another style of underwear.

The study, said to be the largest of its kind to examine links between semen quality and style of underwear, asked men between the ages of 32 and 39 to fill out a survey about the style(s) of underwear worn over the previous 90 days. Choices included bikini, briefs, boxers, jockeys, and other.

Results indicated that a little more than half of the participants (53%) usually wore boxers. Subsequently gathered semen samples, which were analyzed according to World Health Organization guidelines, showed that these men had sperm concentrations that were 25% higher than their non-boxer-wearing counterparts. Their sperm counts were also 17% higher than those of men who wore another style of underwear.

The advantages to boxer wearers don’t stop there. Men who donned boxers also registered higher percentages of motile sperm – those which have the ability to swim through the female reproductive system on a mission to fertilize an egg. The biggest difference in sperm concentration was observed among males who preferred boxers and those who wore briefs and jockeys.

Lidia Mínguez-Alarcón, lead author of the study and research scientist at the Harvard Chan School, said in a press release, “These results point to a relatively easy change that men can make when they and their partners are seeking to become pregnant.”

True enough, but what about men who’ve been wearing tighter fitting underwear for years or decades? Or who simply don’t want to make the change?

They might want to confer greater weight to the science behind the findings rather than the implications of a change in preferred style of dress.

Dr. Richard Quinton, a consultant and senior lecturer in endocrinology at Royal Victoria Infirmary and Newcastle University, was quoted by CNN as saying that scrotal temperature in men is normally lower than their core body temperatures. And the creation of sperm is best achieved at 93°F [34°C].

This is the reason why the testes are located in a way as to hang from the body, he pointed out, noting that the testes also have their own cooling center. Quinton, who did not play a role in the Harvard study, added, "It's been standard advice given to men in fertility clinics throughout the world that they wear loose fitting underwear and avoid taking hot baths. This study validates some of this advice in a much more rigorous and evidence-based manner."

As is the case with most any scientific study, though, not everyone agrees. The CNN report mentions that Sheena Lewis, Emeritus Professor of Reproductive Medicine, Queen's University Belfast, didn’t seem so sure that using different types of underwear amounted to “a scientific way of measuring scrotal heat” – particularly since no information was provided in the study regarding how many hours per day the men wore which types of underwear.

However, fertility expert Dr. Allan Pacey, professor of andrology at the University of Sheffield, was quoted by CNN as saying that the results of the Harvard study “essentially confirm” those of a study involving 2,249 men that Pacey led back in 2012 and which was published in Human Reproduction under the title, “Modifiable and non-modifiable risk factors for poor semen quality”.

Pacey’s study looked a broader range of common lifestyle choices associated with “low-motile sperm concentration”, and, as such, did not zero in exclusively on the subject of the Harvard study. Even so, he said that the new findings underscore his “long-held belief” that men with subpar sperm quality could better their chances at successful conception by keeping the testicle area cool – which includes wearing looser underwear.

He added, “It's also important to note the study is not implying underpants are a major cause of infertility -- in fact, fertility has not been measured. There is a big difference between measuring aspects of sperm quality (as done in this study) and measuring fertility."

Given the latest indicators, though, why wait for more research to confirm scientific suspicion when you can take proactive steps now to protect your assets, without respect to fashion choice?