Clothing determines men’s ability to sire

The ability to sire children is important for most men, especially the young ones keen on starting families.

While a majority are able to impregnate their wives or partners after a few sexual encounters, there are others who struggle with conception for years. Unknown to most affected men, some of the contributors to such fertility challenges are behavioural and can thus be avoided.

Sometimes, the fertility issues stem from seemingly harmless choices such as clothing preferences which is usually pegged on what different people view as fashionable.

A new study led by researchers from the Harvard T.H. Chan School of Public Health has found that men who frequently wear boxers have significantly higher sperm concentrations and total sperm counts than those using other under wear types.

This research, published in the Human Reproduction Journal was conducted in a Fertility Clinic at US-based Massachusetts General Hospital. It suggests that certain types of underwear including jockeys, briefs and bikinis (for men), may inhibit production of sperms. Unlike boxers which offer some breathing space for male reproductive organs, research shows that other underwear types — due to their tight fitting characteristic — can raise temperatures in the scrotum. This adversely affects testicles, hence impeding the production of quality sperms.

Sperms require a precise environment (four degrees cooler than body temperature). It is for this reason that testicles are naturally placed outside the body where the degrees are much lower than the rest of the body.

When exposed to extreme temperatures, the sperms usually begins to die. And if the exposure to heat is prolonged, it can affect sperm production processes, causing the body to produce fewer sperms (low count) which may also be abnormally shaped.

Lidia Mínguez-Alarcón, lead author of the new study from the Harvard Chan School said: "These results of the study point to a relatively easy change that men can make when they and their partners are seeking to become pregnant.”

The researchers stated that while previous research has shown that elevated scrotal temperatures can adversely affect testicular function, studies on whether and how different styles of underwear may impact sperm production have been inconsistent.

For this study, the largest of its kind to look at underwear and semen quality, researchers collected information and semen samples from 656 men who were part of couples that were seeking treatment at the fertility centre.

The men, who were between the ages of 32 and 39, completed a survey that included questions about the style of underwear they wore in the previous three months. Options included boxers, jockeys, bikinis and briefs.

Analysis of semen samples from all men showed that those who put on boxers had a 25 per cent and 17 per cent higher sperm concentrations and quantities (count) respectively, when compared with men who did not primarily wear boxers.

They also had higher percentages of motile sperm, or sperm that are capable of moving through the female reproductive system and fertilising an egg.

The most significant difference in sperm concentration was seen between men who wore boxers and those who wore jockeys and briefs.

In addition, analysis of blood samples collected from 304 of the study participants showed that men who wore boxers had 14 per cent lower levels of the follicle stimulating hormone (FSH) which plays a key role in sperm production.

“This suggests presence of a compensatory mechanism whereby the decreased sperm production among men in tighter underwear signals the brain to boost production of hormones that stimulate the activity of reproductive organs to try increase sperm production.”

Jorge Chavarro, another senior author of the study stated: "Beyond providing additional evidence that underwear choices may impact fertility, our study provides evidence, for the first time, that a seemingly random lifestyle choice could have profound impacts on hormone production in men at both the level of the testicles and the brain."

Aside from tight fitting underwear and trousers, other sources of heat that could destroy sperm quality in men include biking, laptops (placed on the lap) and soaking in hot tubs including saunas.

Even though such activities are usually okay in moderation, men with marginal sperm counts are urged to avoid them while they and their partners are trying to conceive.

Taking cool off breaks from activities that expose testicles to high temperatures can also be helpful such as getting sufficient water when working in hot environments and making frequent trips outside (or to cooler rooms) when spending too much time around hot ovens.