Many thanks to NCBI ROFL for providing this excellent gem of a paper. I was actually going to do another one that I found via their site, but then I saw this one and I HAD TO HAVE IT. And so much additional thanks goes to Jason of the Thoughtful Animal and twitter bud hectocotyli, who managed to find the paper, as Sci only has access to the stacks copy and was about to pull her hair out.
And it was all worth it, my friends! This is a paper of such hilarious awesome that Sci can barely contain her giggles as she writes.
Let me introduce to you...the ball sling.
Just like that. 'Cept it's for a different pair of rocks.
Shafik, A. "Contraceptive efficacy of polyester-induced azoospermia in normal men." Contraception, 1992.
Hehehe. A ball sack for your ball sack. A recepticle for your testicle. A tote for your scrote! I could do this all day...
A sling for your thing. A thong for your dong. A sock for your cock...
Anyway, let me introduce to your a tote for your scrote, made out of the ever classy polyester.
(NSFW pics below the fold. As though that picture of polyester shirts wasn't full of enough horror).
So what did they do? Why did they do it? And what does it all have to do with polyester?
Well. For many years now, scientists have been trying to come up with a reliable form of male contraceptive that...isn't a condom. There's a lot of burden on women when it comes to contraception (in terms of the pill, the ring, the patch, etc), and so for a while scientists have been looking for a way to give men more of an equal say. But hormones don't appear to work very well.
Enter polyester. Apparently sperm are sensitive to polyester (perhaps they are making a strong stand against an ill-advised and possibly wedgie-inducing sartorial choice?). Apparently, previous studies in dogs (!) wearing polyester underpants (!!!) showed that the dogs had reduced sperm count under those conditions (Jason decided to blog this one, and sadly there were no pictures, it's really too bad. But it's a great post anyways!). Good old breathable cotton didn't appear to have any effects on sperm count. Not only that, studies in humans have shown that men who wear polyester underpants sometimes have reduced spermcounts compared to men who wear other fabrics.
Why might this be? Two possible reasons. First, your balls hang low for more than one reason, and one of those reasons is temperature regulation. In order for sperm to mature successfully, they need to be kept a few degrees lower than normal body temperature, so keeping them below the body is a good way to keep things cool. Your testicles (if you happen to be one of the population that has them) will hang lower when it's warm, and if it gets too cool, they will head back up closer to the body cavity to keep at the right temperature. And we all know what happens when it gets TOO cool.
So one of the ways in which poplyester 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.
Whatever the reason, the scientists wanted to test out the effects of a polyester ball sling in men. They took 14 men who were interested in conceiving with their partners (but apparently not in that much of a hurry), and put them in this:
Now doesn't THAT look comfy. My question is, did they get several so they could run them through the wash? What if they DIDN'T?! EWWWWWW.
And they had these dudes wear them for a YEAR. A WHOLE YEAR. While they did their business. The men came in for regular tests of sperm count, rectal (!) vs testicular temperature, measures of electrostatic charge, and a biopsy (!). With a test like this, Sci has to wonder why on earth you'd volunteer. But anyway. Apparently the men didn't complain.
So they wore the scrotal sacks for a year. Within about 4 months, all of the men showed azoospermia, an entire lack of sperm in the ejaculate. They also showed decreases in testicular SIZE (is that a side effect or a feature?) and an increase in testicular temperature, showing that the ball sack was keeping the testicles warmer than normal. In fact, the slings were so effective that after about six months, the semeniferous tubules began to show degeneration. The scientists also noted that the polyester slings resulted in higher electrostatic potentials than before.
Of course, that doesn't sound good, but it turned out it was only temporary. When the slings were removed, the sperm counts returned to normal within five months. Not only that, 5 of the couples who had wanted to become pregnant conceived within a year of the sling's removal.
The scientists concluded that the contraceptive effects of the polyester sling were due to a combination of increases in scrotal temperature and the electrostatic field caused by the polyester. They delve into the issue of electrostatic potential in some detail, but Sci isn't so sure about this one. They talk about negative and positive charges, but what is the MECHANISM? How do excess negative or positive charges prevent sperm maturation? They don't know, and Sci doesn't think they know.
But the thermoregulation thing has potential. The authors talk about how higher temperatures could increase electrostatic fields, but I wonder if maybe the temperature is really what's going on here. It might be good to do a study with polyester vs, say...wool, or something else that keeps the sack at a higher temperature without the creation of the electrostatic field. This might help to determine whether the electrostatic field is a real player here, or whether it's just some nice warm balls.
So, wool on the balls for 12 months! Any volunteers?
Shafik, A. (1992). Contraceptive efficacy of polyester-induced azoospermia in normal men Contraception, 45 (5), 439-451 DOI: 10.1016/0010-7824(92)90157-O