Researchers have recommended that in order to improve sperm health by 25 per cent, men should ditch tight underpants and sleep naked.
The study, carried out by Stanford University in California and the US National Institute of Child Health and Human Development observed 501 men trying to become dads.
Vital reproductive cells in the testicles are preserved at cooler temperatures which cannot be maintained when wearing tight underpants.
Study authors said “Among men in the general population attempting pregnancy, type of underwear worn during the day and to bed is associated with semen quality.
‘Reducing exposure for bed decreases DNA fragmentation; better semen quality parameters are observed in men wearing boxers during the day and none to bed.”