This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Once upon a Thursday night, blog bff Scicurious asked a particular blogger named Jason if he had access to a paper titled, Contraceptive efficacy of polyester-induced azoospermia in normal men. "I certainly hope so," he said. And so he logged in to his university's library proxy website, and searched for the paper.
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She said, "PLEASE PLEASE PLEASE tell me you have access to this article" and then "it's about ball sacks I MUST HAVE IT." As it happens, he did have institutional access. So Jason downloaded it. It was a rather large file, so it took a little while for him to upload it to his Gmail so that he could send it to her. While it was uploading, he began to read the abstract. He said to his friend, "where do you FIND these things" and then, "this (NSFW) picture is seriously disturbing." Sci, being impatient, implored, "SEND IT SEND IT SENT IT. MUST SEEEEE. WANTTTT."
You see, this was no ordinary scientific paper. This was an academic paper which described an experimental method for male contraception. You wonder, "what was this method?" They created little polyester sacks into which hung the scrotums (plural, scrota?) which belonged to these poor gentlemen. For twelve whole months. Sounds pretty terrible to me. Being generally hilarious, our hero Jason titled the file "slinging balls for science for twelve months what the [redacted] were they thinking.pdf" and sent it off. Then our hero and heroine spent the better part of half an hour coming up with rhymes that would surely make Dr. Seuss blush: A recepticle for your testicle. A tote for your scrote. A sling for your thing. A thong for your dong. A sock for your cock... (the last one was his. the rest are Sci's rhymes. she is admittedly better at this game than he is).
Dear Sci went off to blog about the paper, and Jason decided to give the paper a read; it wasn't too long, after all, only twelve pages.
So go read Sci's post about this paper. And then come back here. I'll wait.
And then, in the middle of page two, came the surprise.
And so I said to myself (yeah, I'll switch between third person and first person when I want to, k?) "they did this with DOGS?!!??!! i MUST blog this." And I said to Sci, "ooh! i wanna blog the dog one!!!" Sci said to me, "blog as a companion piece!!!"
And, well, here we are. Underwear for your dog. A cup for your pup. A pouch for your pooch.
The study included 31 male dogs varying between 10 and 18 kilograms. Twelve dogs wore cotton underpants, twelve dogs wore polyester ones, and seven dogs were used as controls. Each dog wore its underwear continuously for TWO WHOLE YEARS. During the course of these two years, the semen character was assessed, testicular temperature measured, various hormone levels checked, and testicular biopsies were examined. Would wearing the underwear result in decreases or full eradication of the sperm? And if so, would one of the materials work better?
Then, the garments were removed, and the same measurements and analyses were conducted for an additional twelve months. Would sperm re-introduce themselves into the semen, once the pooch was free of its modified diaper?
For the polyester group, there were no real changes in testicular temperature. But there was a significant decrease in sperm count and in motile sperms, which are sperms that are good swimmers. The Michael Phelpses of the sperm-o-sphere. There was also a significant increase in abnormal sperm count. There were small but statistically insignificant changes in hormones during the experient. The testicular biopsy showed degeneration in the seminiferous tubules. After the underwear was removed, sperm counts reached pre-experimental levels by the eleventh month in ten of the twelve dogs in that group.
For both the cotton group as well as the control group, there were no changes in any of the measured variables throughout the entire three years of the experiment.
What could account for the observed changes in the polyester group? As Sci has explained:
So one of the ways in which polyester might work to reduce sperm count would be by causing it to be too warm, and thus making it difficult for sperm to mature. And having your balls too warm is probably a better contraceptive option compared to sitting on ice to send your balls in the other direction.The other reason, however, is a bit more odd: electrostatic charge. Apparently polyester rubbing up against the skin produces an electrostatic charge which could somehow prevent sperm maturation.
Since they did not find differences in testicular temperature in the dogs, they assumed that it was the electrostatic potentials that were responsible for the effect. Though they didn't know this for sure.
What I want to know is: did they use boxers or briefs? HAAAAA.
Get it?
Boxers!!?!
Oh, nevermind.
[Update: Interested in more fun testicular science? Here's something from Bora about balls and electricity, and another from Bora about balls and heat.]
Shafik A (1993). Effect of different types of textile fabric on spermatogenesis: an experimental study. Urological research, 21 (5), 367-70. PMID: 8279095