Men who wear boxer shorts produce higher quality semen, study finds, The Independent

It's the largest study to examine the relationship between underwear choice and sperm quality

Physically Demanding Work Tied to Higher Male Fertility. Research found men who reported often lifting or moving heavy objects at work had 46 percent higher sperm concentration and 44 percent higher total

Boxer shorts - Wikipedia

Best Men's Underwear: From Boxers to Briefs

Largest study yet shows type of underwear is linked to men's semen qua

Boxers or briefs? For sperm count, one is better, study finds

(PDF) Impact of environmental factors on human semen quality and male fertility: a narrative review

How Your Choice of Underwear Affects Sperm Production - Seattle Sperm Bank

Boxers or briefs? Prospective dads have an easy choice — Harvard Gazette

A recent Harvard study found men who wore boxers had about 25% more sperm than those who wore briefs