When it comes to male fertility, length matters—the length between the scrotum and anus, that is. New research suggests that measuring a man’s “anogenital distance,” or AGD, is a fast, low-tech, relatively accurate method of getting an idea of the quality of a man’s sperm.
In a new study, University of Rochester professor Shanna Swan and her colleagues broke out the measuring tape and assessed the anus-to-scrotum distance of 126 men born in 1988 or later. The men whose AGD’s were shorter than the average of two inches were 7.3 times more likely to have low sperm counts than their more well-endowed…er, well-distanced, brethren. These men with shorter AGD’s also had low sperm motility and poor sperm morphology.
So why on Earth, you’re wondering, would this be the case?
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Some guys only dream of having a Facebook girlfriend; others are willing to pay a company to create one for them. Soon, lonely dudes with extra cash may feel better about themselves as they interact with a “virtual girlfriend,” convincing their friends that they actually are dating material.
A startup called Cloud Girlfriend plans to provide a service that would post messages on your Facebook wall from a virtual girlfriend (or what they call your “social network girlfriend”). The process is simple: “Step 1: Define your perfect girlfriend. Step 2: We bring her into existence. Step 3: Connect and interact with her publicly on your favorite social network. Step 4: Enjoy a public long distance relationship with your perfect girl.”
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There are certain things you’re not supposed to do during sex and having a heart attack is one of them. We’ve known for a while that bursts of moderate to intense physical activity—including sex—increase heart attack risk, but a few scientists have now put number on that risk. And especially for out-of-shape folks, the diagnosis doesn’t look good (unless you’re aiming for death by sex, of course).
Studying death and sex is a tricky subject: Scientists can’t just round up volunteers, watch them make love, and then note which ones die. So instead they analyzed data from 14 different studies to single out connections between sex, exercise, and the risk of cardiac death or heart attacks.
As the researchers wrote in the Journal of the American Medical Association, “Acute cardiac events were significantly associated with … sexual activity.” When exercising, you’re 3.5 times more likely to get a heart attack, and when having sex (or immediately after sex), you’re 2.7 times more likely.
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When you have your hand up a cow’s behind for the first time, you’re literally groping in the dark. Unable to see what you’re touching and armed with only textbook knowledge of cow anatomy, it’s easy to make a wrong move, which in your first rectal class can mean misdiagnosing a cow pregnancy or not even feeling your first uterus. That’s all changed with the advent of rectal simulators.
Dubbed Breed’n Betsy, this metal-framed simulator with a latex back-end and internal organs allows students to perfect their pregnancy-testing, artificial-insemination, and embryo-transferring techniques before they touch a living cow. After you put on your lubricated glove, you just plunge your hand into the cow and feel around to learn the positions of latex uteri, ovaries, and cervixes. There are also upgrades: A water-filled acrylic tube simulates real-cow temperatures, and you can switch out the latex organs for real ones from your local slaughterhouse (oh goodie!). So after you’ve grown comfortable performing rectal exams on this Frankensteinian mishmash of organs, you can confidently do the same to a living, breathing bovine.
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Spiders and penises are two things most people want to keep far, far apart. Until now. New research suggests that the venom of one aggressive arachnid could be used in future treatments for erectile dysfunction (that is, if it doesn’t kill you first).
Say hello to the Brazilian wandering spider (Phoneutria nigriventer), also known as the armed spider, or as the banana spider. With an over four-inch leg span, this South and Central American native normally creeps around banana plantations, although some have wound up in American supermarkets and Canadian grocery stores. Flaccid fellows beware: On top of severe pain, a single bite from this eight-legged foe can cause you to lose control of your muscles—and if it’s not treated, the bite can screw up your ability to breathe so much so that you slowly die of oxygen deprivation. (more…)
What could be better than two types of sexes? For one organism, the answer isn’t three, but seven! And to top it off, these seven sexes aren’t evenly distributed in a population, although researchers have now developed a mathematical model that can accurately estimate the probabilities in this crap-shoot game of sexual determination.
Meet Tetrahymena thermophila, which in addition to its seven different sexes—conveniently named I, II, III, IV, V, VI, and VII—has such a complex sex life that it requires an extra nucleus. This fuzzy, single-celled critter has a larger macronucleus that takes care of most cellular functions and a smaller micronucleus dedicated to genetic conjugation.
The other odd thing about this one-celled wonder is that the population of the seven sexes are skewed, leading Unversity of Houston researcher Rebecca Zufall and her colleagues to ask: What gives?
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Beauty doesn’t only fade within a lifetime–it also fades genetically over the course of several generations, according to new research. Scientists studying populations of sexually attractive male fruit flies have found that there’s a limit to their evolutionary success–and that there may actually be a disadvantage to being too sexy.
For the study, published in the Proceedings of the National Academy of Sciences, researchers genetically modified male fruit flies, causing them to give off excessive amounts of attractive pheromones. The scientists then introduced a flock of these foxy fellows to a normal fruit fly population. They discovered that the female flies mated with these modified flies more often initially, and the proportion of super-sexy males increased for a while–but the proportions returned to normal after seven generations.
As The New York Times reports:
“Even though we were able to make males more attractive, there must have been a fitness cost,” said Katrina McGuigan, a biologist at the University of Queensland and one of the study’s authors. “While sexual selection is really powerful, there are consequences to nonsexual traits.”
It’s not yet clear what genetic disadvantage these fruit fly ladykillers may have had. But let’s turn to the more urgent question: Is there any carryover implications for humans? The New York Times quotes McGuigan:
“Hard to say, but only that very attractive individuals may well have something wrong with them — they may not be as good as they seem to be at first glance.”
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80beats: How Gut Bacteria Rule the Sex Lives of Fruit Flies
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Image: Wikimedia Commons / A. O’Toole
If you want to impress a female great bustard, going clean-shaven is probably the wrong approach. According to biologist Juan Carlos Alonso and colleagues at the Spanish National Museum of Natural Sciences, the size of a male bustard’s “whiskers and beard” is correlated with its reproductive success.
The great bustard is a beloved but endangered bird found in Spain and other locations scattered across Eurasia. Males of the species are possibly the heaviest flying birds in the world (rivaled only by the male kori bustard), and each sports whisker-like plumage on either side of its beak, along with neck feathers that resemble a beard. They also engage in showy mating displays, strutting about “like a vicar in a tutu,” according to naturalist Chris Packham in this BBC video.
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If you experience feverish, burning-eyed orgasms, don’t rejoice–you should probably consider visiting your doctor. Scientists believe such flu-like symptoms arise when men are allergic to their own semen.
It’s called post orgasmic illness syndrome (POIS). Although the term has been around since 2002, researchers led by Marcel Waldinger, a professor of sexual psychopharmacology at Utrecht University in the Netherlands, have for the first time shown that some men suffer from a semen allergy. Such men, after ejaculating, not only have burning eyes and fever-like feelings that can last for a week, but also feel as tired as post-marathon runners and have noses that run faster than Usain Bolt.
In one study published in the Journal of Sexual Medicine this week, the researchers pricked the skin of 33 POIS-diagnosed men with their own diluted semen, and discovered that nearly 90 percent of them had allergic reactions as a result. As Reuters reports:
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Microscopy often yields striking snapshots, but these colorful compositions have a less-than-glamorous subject: fruit fly intestines.
The insides of these humble critters may help researchers understand the human digestive system. Each of us has something like 500 million intestinal nerve cells, yet little is known about what they’re up to. According to a recent Wellcome Trust press release, fruit fly feces (seen in image 3 above) have helped researchers at the University of Cambridge understand how the gut’s nerve cells affect metabolism.
“We reasoned that what comes out of the gut may be able to tell us about what is going on inside,” says Irene Miguel-Aliaga, who headed the study. “So, we devised a method to extract information about several metabolic features from the flies’ fecal deposits–which are actually rather pretty and don’t smell bad. Then we turned specific neurons on and off and examined what came out.”
Examining fruit fly poo allowed the scientists to assign different functions to different intestinal neurons. Some regulate appetite, for example, while others adjust intestinal water balance during reproduction.
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