In 1695, Nicolaas Hartsoeker published a paper where he depicted sperm cells as each containing a miniature man. We now know that this is not true, but clearly sperm has been on our collective mind for a long time. Researchers from Boston may have provided some new insight into another age-old question: what affects sperm counts: boxers or briefs?
A recent study published in Human Reproduction asked men to report their preference for boxers or briefs and then compared their sperm samples. They measured sperm volume, concentration, and motility.
Each of the circles in the figure above represents one ejaculate, and each white speck contains about 110,000 sperm cells. The left circle depicts ejaculate from a man who reported regularly wearing boxer shorts, and the right circle is from a man who reported wearing briefs or other tight underwear. Men who reported wearing boxers ejaculated a higher concentration of sperm cells.
Tighter underwear (such as briefs) can lead to a higher scrotal temperature, which previous studies have found reduces sperm count. While not definitively causal, the results of this study replicate previous findings on underwear choice and sperm concentration.
Design: David Gaitsgory @dgaitsgo. Source: Type of underwear worn and markers of testicular function among men attending a fertility center. Human Reproduction, Volume 33, Issue 9, 1 September 2018, Pages 1749–1756, https://doi.org/10.1093/humrep/dey259