Going to bed without underwear on may increase your chances of having a baby - (and not just for the obvious reason), according to a new study.
Men who are hoping to become fathers should sleep naked and wear roomy boxer shorts during the day for the best chance of getting their partner pregnant, according to research presented at the annual meeting of the American Society for Reproductive Medicine in Baltimore.
The researchers from the National Institute of Child Health and Human Development, Maryland, and Stanford University followed 500 men for up to 12 months, tracking their underwear choices and monitoring their sperm quality.
They found men who wore boxers during the day and were naked at night had 25% less DNA fragmentation in their sperm compared with men who wore tight briefs day and night.
In layman's terms "fragmentation" means “damage.” Less than 15% damage usually means a very good outcome.
"Type of underwear worn during the day and to bed is associated with semen quality," said the study's lead author.
"Better [sperm] quality parameters are observed in men wearing boxers during the day and none in bed."
Professor.Dr Geeta Nargund, medical director of Create Fertility (www.createhealth.org) and Professor Adam Balen, chair of the British Fertility Society cautioned further research is needed to confirm the findings:
"Any research that potentially helps men to improve their natural fertility with lifestyle changes should be welcomed. Fertility education and prevention of infertility are important," Nargund told HuffPost UK Parents.
"Findings of this study are interesting but we need larger studies to confirm this.
"It is well known that men who expose their testicles to increased temperature by wearing tight underwear or having hot baths can have reduced sperm quality."
Balen concurred: “This study supports the notion that keeping the testes cool is better for sperm function.
"However, we lack hard evidence that this leads to more pregnancies, which ultimately is all that matters.”