“The study is the largest of its kind and also revealed that men who wore boxers also had lower levels of follicle-stimulating hormone (FSH), which stimulates sperm production as compensation for testicular damage that has arisen as a result of increased scrotal temperatures and decreased sperm count and concentration…..”

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

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