A new study from the National Institute of Child Health and Human Development has revealed one simple factor that could be affecting your man's health - whether or not he sleeps naked.
The research, which took into account data from 500 men across a 10 month period, found a direct correlation between the type of underwear worn in bed, and sperm quality and function - a factor which could potentially affect fertility (opens in new tab).
Ultimately, men who chose loose-fitting boxers during the day and wore nothing at night had 25 percent less DNA fragmentation in their sperm compared to the chaps who were wearing tight-fitting pants 24/7.
'Among men in the general population attempting pregnancy, the type of underwear worn during the day and to bed is associated with semen quality,' the lead author of the study explained.
'Reducing exposure for bed decreases DNA fragmentation, and better quality parameters are observed in men wearing boxers during the day and none in bed.'
According to new research, men who sleep naked are likely to have improved sperm quality and function compared with those who wear underwear to bed
Leading fertility expert Allan Pacey, professor of andrology at the University of Sheffield, commented on the findings: 'We have known for some time that men who increase the temperature of their testicles, either through the heat exposure at work or by wearing tight underwear, have poorer semen quality compared to men whose testicles are cooler.'
'What has never adequately been shown is whether men can improve things by changing the choice of their underwear, but this study - although quite small - goes some way to suggest that is true.'
And here are 3 reasons why sleeping naked is good for YOU!
Going commando isn't just good for the fellas - here are three reasons you should be doing it too...
1. Your quality of sleep could improve Many experts agree that sleeping without clothes can help to regulate your body temperature throughout the night, which can aid healthier, deeper sleep. 2. It can aid weight loss Ideal sleep has two cycles - one where your body lowers cortisol levels, and a later one where these levels are increased to give you energy when you wake. If your sleep is interrupted (because you're too hot, perhaps), your body will produce too much cortisol at the wrong time, increasing your appetite and leaving you hungrier than you need to be. The antidote? Sleeping as comfortably as possible, which usually means ditching your PJs...
3. Your love life might get a boost And no, not just because of the obvious... A different survey of 1,000 couples found that 57% of naked sleepers felt happier with their relationship, compared to just 48% of those who went to bed fully clothed. Apparently it's thanks to the skin-on-skin contact, which can increase the 'happy hormone' oxytocin - aww!