Chavarro said that men who chose to wear boxers were found to have a higher concentration of sperm compared to those who wore tight underwear. "Men who may benefit the most are men who've been trying a while and continue to struggle getting their partners pregnant".
That's not the only advantage to looser fitting undergarments: Men who mostly wore boxers also had a higher percentage of what's known as motile sperm.
The theory is that higher temperatures caused by body-hugging underwear interferes with the testicles' ability to produce sperm, a process called spermatogenesis.
A number of small-scale studies previously have linked tighter underwear to lower sperm counts, Chavarro said.More news: Grieving Orca Mother Still Carrying Her Dead Calf. It's Been 16 Days
As part of the study, the men in couples who were seeking fertility treatments were quizzed about their underwear choices and which underwear do they usually prefer.
FSH promotes sperm production.
He cautioned that there is no definitive proof that switching underwear style would make any difference because there may be other factors behind the link between wearing boxers and increased sperm count. It was found that these men had 25% higher sperm concentration than the men who mostly wore tighter-fitting underwear and their total sperm count was 17% higher.
However, those efforts aren't enough.More news: Turkey on the Economic Brink, Explained in a Dozen Charts
Guys with tighter-fitting pants also had higher levels of a hormone that encourages sperm production - likely to compensate for all the seed that gets fried in their high-temperature unmentionables, researchers said. Further the levels of their FSH was 14 percent lower.
Although this study adds new information in the ongoing battle of boxers versus briefs, there are a few important caveats, said Dr. Jennifer Kawwass, medical director of IVF and third party reproduction at the Emory Reproductive Center in Atlanta.
So don't run out and buy a pack of boxers because you're anxious about your sperm counts, Kawwass added.
Although the men were attending hospital for fertility treatment, the researchers say most had good semen quality when compared to the World Health Organization's reference standards, and so the findings could be useful for all men. From the semen samples the team of researchers looked at total count of sperm, motility of the sperms, morphology or appearance of the sperm and the extent of DNA damage to the sperm.More news: Dez Bryant interested in Browns but not ready to play yet