Archive for the ‘Sex & Mating’ Category

Male Birds Can Make Their Sperm Travel Faster for Attractive Females

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spermStrangely enough, it makes sense: A study of red junglefowl, a close relative of chickens, found that males can “adjust the speed and effectiveness of their sperm by allocating more or less seminal fluid to copulations.” The determining factor in this remarkable change of speed is how attractive the male finds the female. According to Discovery News (not to be confused with DISCOVER):

The study…adds to the growing body of evidence that males throughout many promiscuous species in the animal kingdom, including humans, can mate with many females, but chances of fertilization are greater when the female is deemed to be attractive.

Desirable female red junglefowl are easy to identify.

“Female attractiveness is determined by the expression of a sexual ornament — the comb — which is phenotypically and genetically correlated to the number and mass of eggs females lay,” according to study co-authors Charlie Cornwallis of the University of Oxford and the Royal Veterinary College’s Emily O’Connor.

To collect their data, the researchers collected natural ejaculates from dominate and subordinate red junglefowl that had just mated with either an “attractive” or “unattractive” female. What the dedicated won’t do for science.

Related Content:
Discoblog: Warning All Competitive Male Cyclists: Less than 5% of Your Sperm May Be Normal
Discoblog: Prehistoric Crustaceans Produced Sperm Larger than the Animals Themselves
Discoblog: The Strange, Violent Sex Lives of Fruit Flies and Beetles

July 8th, 2009 Tags: , ,
by Melissa Lafsky in Sex & Mating | 2 Comments » | RSS feed | Trackback >

Muriqui Monkeys, However Gentle, Will Kill to Mate

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muriquiThe muriqui have a reputation as being one of the gentlest, most social of the primates—so much so that they’ve been dubbed the “hippy monkey.”But even the sweetest of animals will turn murderous when deprived of basic needs—in this case, sex. New Scientist reports that a gang of six muriqui was spotted pulling a “Lord of the Flies” on an older male:

The victim, an old male, died an hour after receiving savage bites to his face, body and genitals. The observations, published this week in the American Journal of Primatology, show how lifestyles may dramatically alter the behaviour of a species.

So why would these peaceful creatures, close relatives of spider monkeys found only in the Atlantic forests of Brazil, turn to such savagery? NS explains:

The muriqui’s peaceful reputation stems mainly from northern populations that feed on abundant leaves, and where males patiently queue to mate with females.

But in the southern population where the attack took place, fruit is more widely available than in the north, and this may provide a clue to the assault, says Mauricio Talebi of the Federal University of São Paulo-Diadema, Brazil, who led the research.

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July 6th, 2009 Tags: ,
by Melissa Lafsky in Sex & Mating, The Wide (& Strange) World of Animals | 1 Comment » | RSS feed | Trackback >

The Next Pregnancy Must-Have: A Three-Dimensional Model of Your Fetus

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babySome expectant parents are so excited to see their new baby, they just can’t bear to wait nine months. Soon they may not have to, thanks to designer Jorge Lopes of London’s Royal College of Art, who has started making life-size models of unborn babies based on MRI and ultrasound images. ABC News tells us:

“I think we’re at the beginning of a new science, really,” said Stuart Campbell, who heads the obstetrics and gynecology department at King’s College London. “It’s the sort of technique that in the future could be done in a matter of hours. So that the couple could have a model in their hands in a few hours.”

Lopes can create models at various points throughout a pregnancy and has also done models of twins. “It’s amazing to see [a parent's] face when they can hold the models, when they can understand very well the size, the scale,” he said, holding up one of the models. “Something like this is only 12 weeks. It’s very nice to hold this, ‘Oh, this is your son.’”

Some say the models could help parents bond with baby before he or she is born.
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July 1st, 2009 Tags: , ,
by Allison Bond in Sex & Mating, Technology Attacks! | 2 Comments » | RSS feed | Trackback >

Warning All Competitive Male Cyclists: Less than 5% of Your Sperm May Be Normal

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bicyclistFriction and high levels of heat in the groin area, combined with the physical stress of intense training, greatly decreases the number of normal-looking sperm produced by male competitive cyclists, according to a Spanish study.

And we mean “greatly”: The researchers found that the sperm of triathletes who pedaled more than 186 miles per week was, on average, only 4 percent normally sized and shaped. That’s significantly lower than the 15 to 20 percent in the most fertile non-cyclists, and this low count could make conceiving difficult.

Cyclists, therefore, should consider freezing their sperm before commencing training, according to the BBC:

“Fifteen triathletes with an average age of 33 were asked not to have sex for three days before giving a sperm sample. When the results were compared with their training routines, only cycling – not swimming or running – was linked with sperm quality. All of the men – who had been training for an average of nine times a week for eight years – had less than 10% of normal looking sperm, compared with the 15-20% seen in the most fertile men. In those who managed more than 186 miles a week on their bikes, the proportion of sperm that was the correct size and shape had fallen to 4%, the point at which men may struggle to conceive without fertility treatment.

[Lead researcher Diana Vaamonde] added it was unclear whether sperm quality would improve if men retired from the sport but that after years of wear and tear this was unlikely. “Something which could be done would be to have their sperm frozen but when they start training they do not realise what damage can be done to their sperm.”

The researchers said that casual cycling, such as biking to and from work, likely would not negatively impact a man’s fertility. Let’s face it: Because obesity also can cause infertility, most men (and women) should be worried about spending more time on a bicycle, not less.

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Image: flickr/ donjd2

June 29th, 2009 Tags: , ,
by Allison Bond in Contraceptives for Everyone/thing, Sex & Mating | 5 Comments » | RSS feed | Trackback >

Got a Migraine? Chronic Pain? Epilepsy? Try Viagra

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ViagraThe active ingredient in Viagra might hold information leading to new treatments for chronic pain, migraines, Alzheimer’s disease, and epilepsy. Brain cells contain active enzymes that help produce nitric oxide, which gives the little blue pill its power, and scientists think this molecule might help brain cells pass signals to on another. BBC tells us:

Researcher Adam Tozer said: “This prompts the question ‘Why is a molecule that can produce penile erections necessary in the brain? It is hoped that this research will go some way to solving the complexity of communication between brain cells, and therefore provide openings for therapeutic strategies against debilitating conditions. It will also help to shed light on communication in the healthy brain and this will enable a greater understanding of how we think.”

The Leicester team will focus on the junctions – or synapses – between cells that enable them to “talk” to each other. They will examine how nitric oxide can influence this communication.There is evidence to suggest that high levels of nitric oxide have a toxic effect, and may trigger serious brain diseases, such as Alzheimer’s. Rebecca Wood, chief executive of the Alzheimer’s Research Trust said: “It will be interesting to find out what nitric oxide does in the brain, and if it has any role in Alzheimer’s.”This study may help researchers understand how the brain works and how nerve cells communicate with each other. Understanding our thought processes and the brain is crucial to understanding and defeating diseases that affect it.”

Still, we have to wonder about which possible side effects of treatment with nitric oxide might, er, pop up.

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Image: flickr /

June 27th, 2009 Tags: ,
by Allison Bond in Diseases, Injuries, & Other Ailments, Sex & Mating | 10 Comments » | RSS feed | Trackback >

Bad Study of the Week: A Social Life Predisposes Women to Rape

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UPDATE: The article discussed below has since been removed from the Telegraph’s Web site, with no word on whether the story was officially retracted. As several commenters pointed out, the sensationalism of the article differed quite a bit from the actual findings of the article. Essentially, the Telegraph makes it seem as though the study makes the scientifically dubious claim that men are insensitive sex-mongers, while women who behave a certain way encourage men to rape them. So perhaps the title of “Worst Science Article of the Week” is more in order. For more discussion of this matter, see here and here.

Outgoing women who drink socially and wear skirts, beware: You have predisposed yourself to being raped. At least, that’s what a highly questionable study headed by psychologists at the University of Leicester asserts.

The first problems lie in the study subjects, not to mention the methods: To find out the opinions of the male population (through a survey—never the most reliable of data sets) the researchers recruited 101 men from local and university soccer and rugby teams. It’s safe to say that this is not an accurate sample of a diverse male population.

Next, the researchers surveyed the subjects about “how far” they would go with a woman “before calling it a night.” For a subject as emotionally, sociologically, and politically charged as rape, a subject that has many contributing variables, these questions are somewhat of an oversimplification, not to mention potentially misleading to both respondents and researchers.

So what were the results? Here’s what the Telegraph tells us:
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June 23rd, 2009 Tags: , ,
by Allison Bond in Sex & Mating, Worst Science Article of the Week | 10 Comments » | RSS feed | Trackback >

Prehistoric Crustaceans Produced Sperm Larger than the Animals Themselves

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spermIt’s hard enough for us humans to fight for a mate. But for the now-extinct mussel-like creatures known as ostracods, which lived on Earth about 100 million years ago, “getting in” was only part of the battle.

That’s where giant sperm comes in: Females copulated with multiple males, so it was up for the sperm themselves to duke it out inside of the female’s body. New research based on microfossils of these ancient creatures, led by Dr. Renate Matzke-Karasz in Munich, shows that a male’s sperm may have been even larger than the animal itself. And ostracods aren’t the only animals to produce mega-sperm, according to Reuters:

Giant sperm are still around today. A human sperm, for example, would have to be 40 meters long to measure up against a fruit fly’s. The insect is only a few millimeters in size but can produce 6 cm-long (2.5 inch) coiled sperm.

Now that’s impressive.

Related Content:
Discoblog: Girl or Boy? At-Home Test Reveals Baby’s Gender During Pregnancy
Discoblog: Does the Taste of Semen Have Evolutionary Roots?
Discoblog: Is Virginity Loss Really All in Your Genes?

Image: flickr / notsogoodphotography

June 18th, 2009 Tags: , ,
by Allison Bond in Sex & Mating, The Ocean & All Its (Endangered) Wonders, The Wide (& Strange) World of Animals | 3 Comments » | RSS feed | Trackback >

Girl or Boy? At-Home Test Reveals Baby’s Gender During Pregnancy

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babyIn the past, an expectant mother who wanted to know the gender of her unborn baby had to wait for a sonogram 20 weeks into her pregnancy. But now an at-home test can determine a baby’s sex only 10 weeks in, with 78 to 80 percent accuracy, according to IntelliGender, the test’s creator.

When we asked the company’s rep exactly how the test worked, we were told what we pretty much already knew: It’s an analysis of urine in which chemicals react with hormones to indicate the gender of the baby. It takes about 10 minutes for the urine sample to turn either orange (for a girl) or green (for a boy).  Interestingly, recent sexual activity can yield a false “boy” result.
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June 9th, 2009 Tags: , ,
by Allison Bond in Sex & Mating, Technology Attacks! | 9 Comments » | RSS feed | Trackback >

Two Twins, Two Dads: DNA Test Proves “Twins” Born to Different Fathers

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test.jpgDespite the fact that they were born at the same time to the same mother, Justin and Jordan look nothing like twins, besides having the same skin color. In fact, they look so different that James Harrison, the supposed father, decided to request a paternity test. Turns out, his instincts were right: One of the infants is his child, and the other is not.

Mia Washington, the mother of the “twins,” admitted to cheating on Harrison, her fiancé, prior to becoming pregnant. But she didn’t have any idea the pregnancy was a result of two separate sets of sperm.

Biologically speaking, this can happen when two or more eggs from the same woman are fertilized during the same ovulation period by two different men. When this rare event occurs, it is called heteropaternal superfecundation—and we really mean rare: There have only been about 10 other cases of this, according to the president of Clear Diagnostics’ DNA lab, Genny Thibodeaux. And in those cases, it was more obvious because the children were of different ethnic backgrounds.

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May 18th, 2009 Tags: , , ,
by Boonsri Dickinson in Sex & Mating | 10 Comments » | RSS feed | Trackback >

Need to Deliver a Baby? Let YouTube Show You How.

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baby.jpgYou can learn to solve a Rubik’s cube from YouTube—so why not how to deliver a baby?

Twenty-eight-year-old Marc Stephens, now a father of four, had planned an at-home birth with his wife, Jo, but the hospital had no midwives available when baby time came a-calling. So instead, he tapped his memory for lessons he’d learned about childbirth from a series of how-to videos on YouTube.

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April 30th, 2009 Tags: , , ,
by Rachel Cernansky in Sex & Mating, Technology Attacks! | No Comments » | RSS feed | Trackback >