However, the study does not explore whether the occupation of the men and the length of time that they spend seated were also important, he said. Those men had 25 percent higher sperm concentrations and 17 percent higher total sperm counts, compared with men who did not, the study found.
The full findings are present in the journal- Human Reproduction.
Lead author, Lidia Mínguez-Alarcon, said, "These results point to a relatively easy change that men can make when they and their partners are seeking to become pregnant". Each provided semen and blood samples and they were asked about the style of underwear they wore most frequently in the preceding three months.
Men who primarily wore boxer shorts had a 25 per cent higher sperm concentration, a 17 per cent higher total sperm count and 33 per cent more swimming sperm in a single ejaculation than people with tighter trousers, the study found.
But if that isn't enough to put men off of wearing them in favour of boxers, this new study just might.
That is not the only benefit for people who wear boxers or any loose-fitting underwear, these men also have a higher percentage of what is known as motile sperm. According to the study, these sperms are more adept at moving through the female reproductive system and fertilizing an egg.
Previous research has linked increased scrotal temperatures to adverse testicular function, so the team of experts set out to examine whether a man's type of underwear had any effect.
Commenting on the research, Prof Allan Pacey, Professor of Andrology, University of Sheffield, said: "This study confirms my long-held belief that men with poor sperm quality could potentially improve things by wearing looser underwear and keeping their testicles as cool as possible". In that, the decreased sperm production among men in tighter underwear signals the brain to boost production of hormones that stimulate the activity of the gonads to try to increase sperm production.