A better understanding how a sperm swims its way toward an egg could help inform new treatments for male infertility. Researchers from the University of York have now come up with a mathematical formula to model how large numbers of moving sperm interact with fluid they're swimming through. From the University:

By analysing the head and tail movements of the sperm, researchers have now shown that the sperm moves the fluid in a coordinated rhythmic way, which can be captured to form a relatively simple mathematical formula. This means complex and expensive computer simulations are no longer needed to understand how the fluid moves as the sperm swim.

The research demonstrated that the sperm has to make multiple contradictory movements, such as moving backwards, in order to propel it forward towards the egg.

The whip-like tail of the sperm has a particular rhythm that pulls the head backwards and sideways to create a jerky fluid flow, countering some of the intense friction that is created due to their diminutive sizes.

“It is true when scientists say how miraculous it is that a sperm ever reaches an egg, but the human body has a very sophisticated system of making sure the right cells come together," (says University of York mathematician Hermes Gadêlha.)

“You would assume that the jerky movements of the sperm would have a very random impact on the fluid flow around it, making it even more difficult for competing sperm cells to navigate through it, but in fact you see well defined patterns forming in the fluid around the sperm.

YO is an FDA-cleared sperm quality analyzer for your smartphone. It consists of a detachable mini microscope and light that clips to your mobile phone. You "acquire" a sperm sample, drop it into the YO Clip, and the app records a video of your sperm in action and analyzes the activity. Available in January, you can pre-order two tests for $50. I bet the app has social media integration so if you have strong swimmers, you can proudly share the proof with your friends.

"Extensive testing has been performed on the YO Home Sperm Test—over four years to be exact," Marcia Deutsch, CEO of Medical Electronic Systems, the parent company of YO Sperm Test and producer of commercial-grade semen analyzers for major labs, tells Fit Pregnancy. "The technology is able to read the sperm sample 99 percent of the time, as long as the instructions are followed. [If it can read the test] the results are more than 97 percent accurate based on FDA studies of 316 participants."

Because it's an over-the-counter product, Deutsch says the test can't reveal actual values, but rather gives a reading of "low" or "moderate/normal" based on World Health Organization (WHO) guidelines for sperm motility (how well they move) and concentration (how many there are). The test reports a composite of these two parameters called "motile sperm concentration," or the number of moving sperm.

YO Sperm Test (via Uncrate) Read the rest

An educational video for you, from Japan. [Video Link. Thanks, Heather!] Read the rest

The hunt for an effective, reversible, and socially acceptable male birth control continues. The newest target: The smooth muscle that makes up the tubes connecting the testes to the urethra. This needs to contract in order for sperm to reach their final destination. Now, scientists have shown that you can make mice sterile by eliminating their ability to contract that muscle. The result: A mouse with a dry ejaculation but which is still "pelvis thrusting with appropriate vigor and frequency".

This is a long way from becoming reversible treatment for human gentlemen, though. Right now, probably the most promising male birth control is RISUG, in which a clear polymer gel is injected into the vas deferens. The gel doesn't block the tube up completely, but it does seem to prevent sperm from successfully reaching the urethra and being capable of fertilizing an egg. RISUG is in Phase III clinical trials in India, but, even then, there are still safety questions about it and, so far, it's only been proven to be reversible in tests on non-human primates.

Image: Some rights reserved by Iqbal Osman1

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In a study of 6,455 semen samples (yup), scientists at Israel's Ben-Gurion University of the Negev found that human sperm were most atheletic — and were found in the highest concentrations — in winter. There was a marked decrease in sperm motility and numbers in spring, summer, and fall. It's an interesting and logical addendum to the fact that sperm counts and motility decrease in men who subject their testicles to warm conditions; in hot tubs, say, or a pair of overly tight underpants. Read the rest

The latest prospect in male contraception: blasting your reproductive organs with ultrasound to halt sperm production. Experiments on rats using the technique dropped sperm counts to 10m sperm per milliliter; under 15m sperm per milliliter is considered infertile in humans.

The results were published in the journal of Reproductive Biology and Edocrinology. Andrologists warn that much more work is needed to rule out the possibility of damaged, rather than dead sperm. From the BBC:

Lead researcher Dr James Tsuruta said: "Further studies are required to determine how long the contraceptive effect lasts and if it is safe to use multiple times." The team needs to ensure that the ultrasound produces a reversible effect, contraception not sterilisation, as well as investigate whether there would be cumulative damage from repeated doses.

Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said: "It's a nice idea, but a lot more work is needed." He said that it was likely that there would be recovery of sperm production, but the "sperm might be damaged and any baby might be damaged" when sperm production resumed.

In the meantime, I understand that blasting Nickelback is also an effective contraceptive.

Testicular zap 'may stop sperm' [BBC] Read the rest