This Popular Men’s Fashion Trend Could Be Behind Lower Sperm Counts

zizi_mentos/ShutterstockFollowing the news that sperm counts in men have plummeted in the last 40 years, scientists—and couples trying to conceive—have been trying to figure out why. While diet and lifestyle factors are important, another possible cause lays the blame firmly at fashion’s door.

Men, it may be time to bid farewell to your beloved skinny jeans, because there’s a chance those tight pants could be interfering with your sperm production.

“There are things in a man’s life that will change how his testicles function,” explains men’s health expert Allan Pacey from the University of Sheffield in England. According to Pacey, as reported on Inverse Science, “the single biggest risk factor for how many swimming sperm [a man] produced each day was whether he is wearing tight pants or loose pants.”

Basically, the tighter a man’s clothes are around his genitals, the further his testicles will be pushed towards the warm core of the body. And heat is not the scrotum’s friend—at least when it comes to producing healthy sperm. Sperm need to be active and flexible to make a successful journey to their final destination (the egg), and their ideal temp is a two to three degrees below 98.6 (which is why the testicles hang separately from the body); heat, be it from a laptop, heat pack, hot tub or the confines of skinny jeans, can slow sperm down.

“There is a maximum amount of sperm that [a man] can produce each day, based on the size of his testicles,” reveals Pacey. However, most men never reach that top number. “Everything he does decreases the optimization of that count,” says Pacey.

Don’t panic if you just can’t get enough of your skinny jeans (or tight pants, or Speedos). Any damage they may have done is temporary—and reversible! Because it takes around three months to make a fresh batch of sperm, from start to finish, it should only take three months of wearing looser pants to maintain a more sperm-friendly temperature. Provided you ditch the skinnies, of course.

Satrorial choices aside, there are many ways a man can boost his fertility. Experts recommend quitting smoking, reducing alcohol intake, sleeping seven to eight hours per night, limiting caffeine consumption, exercising moderately, and eating a diet rich in fresh fruits and vegetables.