Friday Weird Science: a tote for your scrote, a recepticle for your testicle.

Jun 18 2010 Published by under Friday Weird Science

This post was chosen as an Editor's Selection for
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

24 responses so far

  • Snarkyxanf says:

    I never expected to see a product that might have the label "Warning: may cause excessively sweaty balls".
    However, if they do a trial with a wool replacement, I recommend that the product be named the cock sock. Quite possibly more effective than a lambskin condom.

  • A. says:

    I non-ironically want those shirts. I am not nearly as embarrassed about this as I should be.

  • Aegis says:

    Wool sling?
    I'd feel pretty sheepish if I ended up having to explain that one to the missus.

  • AK says:

    Big question: What happened to the men's sex drive during the test period, and did it recover to normal afterwords?
    Regarding the effect of heat on sperm production, I remember reading once about some "primitive" folk (either in South America or New Guinea) whose men soaked their testicles in hot water for long periods as a contraceptive. (A quick search didn't find any relevant literature, but did find this, which shows that the effect of heat on sperm production has been known in Western society "since ancient times and is mentioned in Hippocratic writings from the fifth century B.C.")
    Interestingly, testicles in marsupials drop in front of (anterior to) the penis rather than behind as is the case in Eutherian ("placental") mammals. This suggests to me that they dropped independently, probably with a rise in body temperature in response to a global temperature rise.
    (Obviously, the hypothetical global temperature rise wouldn't have caused all the extant marsupials and Eutherians to drop their testicles, rather it would have killed off all but one lineage of each that had already pre-adapted in this fashion. Considering that mammals can cool themselves through evaporation via panting and sweat, the key measure would have been the maximum frequent dew point rather than actual temperature, which IMO would relate to the average surface temperature of tropical and equatorial oceans.)

  • Peter says:

    At a British tourist shop, many years ago, ran across a "woolen willy warmer" in the novelty section.
    Basically a knit condom with integral satchel or the balls... Knitted in a Union Jack pattern. Wish I'd got one at the time, no idea where to get one now...

  • Peter says:

    The google is our friend... Not quite the same one, but...

  • Pascale says:

    So do they have to wear them constantly? Or would wearing them all day or overnight be sufficient? Do you have to leave it on during sex?
    WE NEED ANSWERS. Oh, wait, I personally don't.

  • Art says:

    The whole idea of electrostatic charges on testicles, sweaty, wet and salty here in the deep south (not to be confused with Chef's "Chocolate Salty Balls"), seems odd.
    I would also think that any charge would have less to do with the friction against skin than friction against hair.

  • OK, so on a totally serious note... So I've heard a lot about a steady reduction in sperm count over the past century or so. People seem to be blaming estrogen mimics in the water, etc... but doesn't this study suggest that it could be due to different styles of underwear and materials used for them?

  • Silver Fox says:

    Or global warming?

  • Torbjörn Larsson, OM says:

    That is pure igNoble material, in more than one sense.
    Besides merely having a correlation between electrostatic charges and azoospermia, there really isn't much to commend in a study that notes degeneration in their subjects and not act on it. With having a pre-study on animals with only ~ 80 % full recovery, at that. The childishness aside, isn't that the real story here?
    Leaving the ethics, I don't think you can expect weak electrostatics to affect body function. Yes, it is possible that a field would persist in the clothes. The paper claim to have measured such. (Paywall.) But the conductivity of the body and the Faraday cage type shielding by the dipole layer cell membranes would not leave much field for an effect on biology.
    Btw, I'm pretty certain that the cell membrane dipole field, inside the cells themselves to boot [!], would be far stronger; but it is Saturday and I'm too lazy to do that estimate. But as a comparison to biological fields, the resting action potential of - 70 mV over an axon would mean a dipole charge potential of ~ 700 MV/m^2 over the membranes of 1 um nerve cells. The observed charge potential was ~ 200 - 400 V/m^2.
    Temperature OTOH is the main suspected (thus the scrotum) and observed cause for sperm dysfunction. I believe a known contraceptive is to have a long enough sauna bath, it will take hours for enough new sperm to mature to be effective by density. I don't know how effective the procedure is though.
    Here is an older (1998) study on sauna bath effects on sperm characteristics, that describes other temp observations too. Unfortunately they didn't have the means to study the contraceptive effect.

  • Torbjörn Larsson, OM says:

    Oops, I'll need to amend that.
    - The dipole charge would be the potential difference, which is more like 100 mV. (Of course, since I didn't bother with the actual geometry of axons, it is a rough estimate anyway.)
    - Better make that "suspected contraceptive" of sauna. It may well be that I'm pushing an urban legend. 🙁

  • Torbjörn Larsson, OM says:

    ... and somehow I tripped on my own laziness, since I put in "charge potential" for the dipole. It was supposed to be a comparison of charge, damn it; the actual potential is not comparable that way. Oh, well.

  • Autistic Lurker says:

    So, wool on the balls for 12 months! Any volunteers?
    how much do you pay?

  • canary bob says:

    I have known since I was a teenager that polyester is one of the things I simply cannot wear, as it causes my skin to itch and break out in rashes and pimples. Synthetic fabrics made from petroleum constantly outgas small amounts of organic compounds as the molecules they are made of break down. People like myself are particularly sensitive to these compounds, while most people hardly notice. Maybe someone should study the effects of synthetic vs. natural fibers on sperm production, rather than barking up the same old "temperature" tree. Meanwhile, I'll take all-natural fibers please, especially on my ball sack.

  • Tom says:

    Polyester for your Uncle Fester.

  • daedalus2u says:

    An effect due to electrostatic charge is not possible. Skin, blood and all biological tissues are quite conductive. That is why you can measure electrical activity inside the body, because it is conductive.
    What affects cells, is the voltage across cell membranes. It is the voltage across a voltage gated channel that affects it. Membranes are quite thin, and the potentials that cause the voltages across the membranes are ~50 mV. With a 10 nM thickness, that is an electric field of ~5 million volts per meter. Air breaks down at less than 3 million volts per meter (a in lightning).
    I remember reading about this being tried in India as a form of birth control. It produced the unacceptable side effect of reduced libido in men.
    How “reversible” this might be is unknown. It might be “reversible” in young men, but long term use might increase the senescence of the testis and produce infertility or “male menopause” at a much earlier age than would otherwise occur. Non-specific thermal effects might also damage sperm, either via denaturing of proteins necessary for appropriate methylation of DNA, or through non-optimum replication and repair of DNA. Rates of birth defects might go up.

  • Jim says:

    Sci, I saw this and thought of you 😉 I fear your recent twitter stream has left an indelible association in my mind.

  • K1 says:

    So does this mean those "sexy underwear" websites that sell "push out" underwear for men (i.e. undies that makes men's "packages" stick out in their pants all the time) will actually increase fertility? That I can justify buying them now?

  • [...] work in this study is based on previous work in humans and in dogs (which Jason and I both covered in one very EPIC day on blogs and twitter. Hehe, recepticle for your [...]

  • [...] and some even wear briefs, snuggling that junk up against the body cavity. In fact, wrapping the testicles up tight (or even just embarrassing them with polyester) can decrease sperm count to the point of [...]

  • [...] A tote for your scrote, a recepticle for your testicle. [...]