The advice to wear boxer shorts instead of briefs seems reasonable at first glance, since

for testes to produce sufficient quality and quantity of sperm, the temperature of testes must be lower than the core body temperature.

But is the temperature difference between boxers and briefs actually high enough to matter?
This study from 1998 suggests "NO":

In our study there was no difference in scrotal temperature depending on underwear type. It is unlikely that underwear type has a significant effect on male fertility.

My question:
Are there studies that support the claim that switching from briefs to boxer shorts (or other "loose" undergarments) can improve fertility?

  • 7
    May I suggest you change the question from "Can boxer shorts improve fertility?" to "Do men's briefs reduce fertility?" to put the focus on the alleged problem. (If true, presumably "going commando", or joining a nudist group, would have a similar benefit.)
    – Oddthinking
    Commented May 30, 2011 at 11:48
  • 3
    If they have to be lower than core body temperature (37 degrees C) how are fertility rates different in countries where the actual outside temperature is often close to or above normal body temperature. For instance, it's 40 degrees in New Delhi today. Also, note, India does not seem to have a problem with making people.
    – Kibbee
    Commented May 30, 2011 at 12:45
  • 3
    I agree with @Odd. Assuming that being naked is the norm, adding boxer briefs is unlikely to improve fertility. Even assuming that briefs are the norm, would switching back to boxers undo any damage (which may or may not be happening anyway)? It is probably more clear to just ask "Do briefs reduce fertility?" or "Does your underwear impact your fertility?"
    – MrHen
    Commented May 30, 2011 at 13:31
  • 4
    @chris: [citation needed]. :P
    – Jon Purdy
    Commented May 30, 2011 at 18:27
  • 2
    @chris: The article you mention manages to not cite any references to back up any of the many claims it makes. Phrases like "Some women", "Study shows", "Some doctors", etc. already make the article suspect.
    – In silico
    Commented May 30, 2011 at 22:15

1 Answer 1


According to this Health Library article:

A few studies have shown a decrease in sperm concentration and motility when subjects wore tight-fitting underwear compared to loose-fitting underwear (such as boxer shorts). It is worth noting that most of these studies were conducted on very small numbers of subjects. One study published in the Lancet included nine subjects; another published in Reproductive Toxicology studied only two subjects.

However small, both of those studies concluded that wearing tight-fitting underwear does increase scrotal temperature enough to significantly reduce sperm count and motility. Neither of these studies, though, suggested that the deleterious effect on sperm was long-lasting.

One of the largest studies supporting the claim was conducted on 50 men at Leibig University in Germany. Its results indicated that high scrotal temperatures (defined as near body core temperature) negatively affected spermatogenesis (the development of mature sperm cells). The German study, published in Human Reproduction, measured scrotal temperatures on men wearing cotton jockey briefs, cotton boxer shorts, or no underwear, and compared the temperatures after the men completed physical activity (walking for 45 minutes on a treadmill), and after they sat in a fixed position for 45 minutes. The study found significantly higher scrotal temperatures while the subjects wore jockey briefs versus boxers, regardless of activity level, and the lowest scrotal temperatures when the subjects wore no undergarments.

It lists references at the bottom of the article.

So it looks like there are studies that support the claim which answers your question. However, the numbers are significantly low to make a solid claim.

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