Last updated on Jul 7th, 2020 at 04:16 pm

Boxers or briefs – the type of underwear a man wears could affect semen quality, which affects fertility

If you and your man are trying for a baby, it might be time to invest in new underwear for him.

Research has found that men who wear boxer shorts have higher sperm concentrations than men who wear tighter fitting underwear.

The researchers also found that boxer shorts-wearing men had lower levels of follicle-stimulating hormone (FSH), compared to men who most frequently wore briefs, “bikinis” (very brief briefs), “jockeys” (underwear that finishes just above the knee) or other tight-fitting underwear.

FSH stimulates sperm production and the researchers say that these findings suggest that it kicks into gear when it needs to compensate for testicular damage from increasing scrotal temperatures and decreasing sperm counts and concentration.

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Related: 3 Factors linked to infertility (and what you can do about them)

Over 600 men studied

This is the largest study to compare underwear type to semen quality and included 656 men.

Men who wear boxer shorts have higher sperm concentrations than men who wear tighter fitting underwear

Unlike previous studies, researchers also looked at a variety of indicators of testicular function, such as reproductive hormones and sperm DNA damage. These can help in understanding how choices of underwear affect the key regulator of sexual development and reproduction, the hypothalamic-pituitary-gonadal axis.

Researchers recruited the male partners of couples who were seeking infertility treatment at the Massachusetts General Hospital between 2000 and 2017.

Among the 656 men, 53% (345) reported that they usually wore boxer shorts. They tended to be younger, slimmer and more likely to take hot baths or Jacuzzis than the men who wore other, more tightly fitting underwear.

Men who primarily wore boxer shorts had a statistically significant 25% higher sperm concentration, 17% higher total sperm count, 33% more swimming sperm in a single ejaculate and 14% lower FSH levels than men who did not usually wear boxers. In addition, more sperm was correctly shaped, although this result was not statistically significant.

Source: European Society of Human Reproduction and Embryology via

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